Why Join the Naturalists?

We can’t survive without access to the fresh air, water, food, shelter, spiritual enrichment, aesthetics, personal restoration, and nature’s other essentials that allow us to celebrate life on this third planet from the sun. Our very physical and mental health depend on nature. But our popular cultures have detached us from Earth’s natural systems and cycles, the very forces and processes that rule our world, resulting in perilous dysfunctions that even AI cannot treat or resolve. And have you checked the news lately? Our nature deficit disorders are having tragic consequences that threaten humans, millions of other species, and the very future of our planet.

The UC California Naturalist statewide natural resource education and service program is coming to the rescue! This extraordinary program fosters “a diverse community of naturalists and promotes stewardship of California’s natural resources through education and service.” They draw you in with refreshing truth telling: “We cannot protect and restore California’s unique ecology without an environmentally literate, engaged public.” … and … “Becoming a naturalist offers a chance to explore nature and deepen your understanding of how nature works.” And then they make you offers you can’t refuse: “Are you interested in nature? Do you love CA’s diverse ecosystems? Embark on an immersive adventure with experts. Deepen your understanding of ecology and forge lasting friendships. This course has graduated career starters through retirees, all learning together to become a community of Certified California Naturalists.” How could we resist this magical week in Yosemite?

Follow Us on this Magical Natural History Tour

Join me on this journey as I share some of our day-to-day discoveries from the experts in the field who live this stuff. Images and excerpts from more than 32 pages of field notes prove that, even after leading hundreds of field classes and field trips with thousands of my students and colleagues over more than three decades, we and I will never stop learning. (The stories here are taken from my personal field notes and some occasional background research. All photos are mine and are not edited or manipulated in any way.) Let your curiosity fly like the clouds and wings over Half Dome in this Yosemite natural history expedition.   

Chris Cameron was our organizer, leader, and master instructor for these exceptional learning experiences. Without Chris, a one-of-a-kind tour guide and educator, we wouldn’t be able to retrace our steps because there wouldn’t be any. He demonstrated phenomenal skills in gathering seasoned professionals and curious students together to learn within nature’s living laboratories. And his people skills are the icing on the cake!    

Each day of our expedition gets its own page in this story; simply click to the page that matches the day and/or subject. You are encouraged to follow me chronologically to soak in the full benefits. Here’s how it’s all organized:

Day/Page One (Saturday, 4-12-2025): From the Central Valley up to ECCO in Oakhurst
Day/Page Two (Sunday, 4-13-2025): Geology, Creation, and More than 100 Million Years
Day/Page Three (Monday, 4-14-2025): Healthy Forests and Roaring Falls
Day/page Four (Tuesday, 4-15-2025): Cliffs, Bats, Fires, Technology and Botany
Day/Page Five (Wednesday, 4-16-2025): Following the Trail to Native Americans and American Settlers
Day/Page Six (Thursday 4-17-2025): Grazing, Logging, and Hunting, Oh My!
Day/Page Seven (Friday 4-18-2025): Sharing Our Discoveries

Day One (Saturday, 4-12-2025): From the Central Valley up to ECCO in Oakhurst:

A drive north along Hwy 41 from Fresno eventually takes you out of the Central Valley, which shines as the country’s most productive agricultural landscapes. This sprawling valley is vital in making California the number one agricultural state in the nation, as the state generates well more than $50 billion income per year from farm products.     

As the road gradually slopes up toward Sierra Nevada foothills, we find ourselves surrounded by open grasslands that recall the vast prairies that once dominated the Golden State’s inland valleys before the Spanish arrived. You will notice cattle grazing on pastoral rolling hills, landscapes occasionally interrupted and sliced by serpentine streams and rivers meandering from east to west, out of higher elevations and into the valley. (These lush narrow riparian strips are what remains (less than 10%) of the broad gallery forests that once extended on both sides of streams and rivers flowing out of the Sierra Nevada.) Today’s hills turn verdant green by April and erupt into rainbow displays of wildflowers such as lupine. But the grasses and flowers will soon dehydrate to the golden browns of punishing summer drought, leaving their seeds in parched soils, waiting for next winter’s rains and next spring’s renewed fantastical displays.

But another invader has recently rivaled the seasonal nonnative grasses on these gentle slopes at the base of the Sierra Nevada Mountains: humans and their developments. Developers are gobbling up some of these landscapes and attracting people who want to escape urban crowds, chaos, and traffic. “Build it and they will come” continues to spread across these landscapes that tourists have been passing by for decades on their way to the high country. Entire wannabe self-sufficient communities have been sprouting and extending over the grasslands and oak woodlands. And the changes are not coming without controversy. As these ecosystems are scraped up and paved, some locals are watching their reasons for living here disappear, while recent arrivals find relative peace and quiet in their perceived bucolic settings. Talk of limited water and other resources, habitat destruction, loss of open spaces, pollution, land values, affordable housing, and increasing traffic congestion is replacing the traditional agrarian discourse and cultures. Such noticeable changes are stretching and then redefining our perceptions of wildland-urban interfaces. The end of this world as we knew it may be just one more development away.

Once we get up above about 1,000’ elevation, where a little more precipitation falls and temperatures are a bit cooler, an assortment of scattered oak trees pops up above the ground cover. At about 2,000’, the woodlands thicken and diversify to include gray pine and other drought-tolerant trees. These scraggly pines with long, grayish needles and big cones often appear bent and twisted as though they were dancing through the night and were suddenly frozen in a pose by the morning light, waiting for summer’s fire or winter’s first merciful rehydrating showers. As we progress higher, slopes tend to steepen and we notice mixed pine forests as we look up toward snow in the distant high country. (We will revisit Sierra Nevada’s vegetation zones in more detail during the next few days.) We drop down into the town of Oakhurst (elevation 2,274’), nestled in its little valley that many consider the gateway to Yosemite. Traveling up and a little farther north, we finally turn off Hwy 41 and will settle, hang our hats, and share tasty meals at ECCO each night, which is a pretty typical option for tour and educational groups looking for base camps in and near Yosemite: “The Episcopal Conference Center Oakhurst (ECCO) has been serving the religious, educational and non-profit conference and retreat needs of Fresno, Madera, Mariposa and the rest of California’s Central Valley since 1982.”       

This is where we can hear Yosemite calling from just several miles away. The rolling landscapes in and around ECCO (about 3,100’ ASL) is populated with mostly open oak and pine woodland. The deciduous oak trees are just beginning to sprout by mid-April, careful to avoid any late-season freezes. A giant pond with a fountain demands attention, decorating the property and attracting more than our senses. Depending on the season, an assortment of waterfowl and other wildlife visit or live around the water (more than 100 species of birds have been recorded there), demonstrating animal behaviors that deserve a line or two in our field notebooks.

Wild turkeys are particularly entertaining as they dive out of their trees (where they roost at night to avoid predators) early in the morning and trot around during the day. Their toe-walking and dragging one foot in front of the other leaves an arrowhead-like trail. Turkeys are not native to California, but numerous attempts to introduce them finally became successful so that their numbers multiplied since the 1960s until they now total about 250,000 in the state. These omnivores mate and lay their eggs during spring. Gestation takes about a month and they are most vulnerable to predators (such as coyote, bobcats, foxes, some birds, and domesticated animals) after hatching. Adults may become nuisances around humans as they show aggression with their flapping and pecking; their droppings also get pretty messy. They’ve been known to damage gardens and attack their reflections in windows and on the sides of cars.  

The turkeys remind us that every species of plant and animal, every landscape, rock, cloud, water drop, and weather event have captivating natural history stories to tell. Informative and useful narratives grow from research that connects all of us to our natural world. We can see why this is just one of the naturalist programs across the US. Master instructor Chris Cameron started our course by summarizing how we celebrate biodiversity with environmental literacy, scientific and social understanding, by honing our interpretive skills, and practicing collaborative conservation. We reviewed our state’s bioregions and geomorphic provinces (from page 29 in our required California Naturalist Handbook), which coincide with the physiographic regions we have explored in numerous stories on this website and in my publications. And we recognized how the California Floristic Province, a biological hotspot with its thousands of species that include a large percentage of endemics, is experiencing a biodiversity crises as increasing numbers of those unique plants and animals are threatened with extinction. We recognize how naturalists’ work has become crucial as we observe, communicate, and act to build essential links between scientists and the average person. After dinner, our first day and evening ended with my presentation that summarized some fascinating properties of water and the weather patterns and climates that rule over our plant communities, topics we have highlighted on this website and in my recent California Sky Watcher book and statewide tour.      

Click (below) to the next page and day.

The post Cal Naturalists Invade Yosemite first appeared on Rediscovering the Golden State.

Fire has been our friend for millennia. Humans have enjoyed the benefits of controlled fires used to cook our food, heat our spaces, comfort us as we sat around our campfires, provide light and protection, clear and manage landscapes, burn waste, and power our engines. By contrast, many of us have also been terrorized by the unforgettable life-and-death experience of getting too close to an out-of-control blaze. That’s when capricious fire can be likened to an unpredictable vicious predator that breaks out of its cage, or a scene from one of those Jurassic Park movies when Tyrannosaurus rex crashes through its confining barriers. Suddenly, anything goes and we are at the mercy of what we thought we had under our control. Fire is another example of how the very nature that nurtures us can suddenly morph into the misadventure or calamity that kills us. Humans’ relationship with fire has always been complex, but it would be difficult to imagine a place where this partnership has been more misunderstood, abused, researched, and reevaluated, than in California during the last several decades.

During the 20th Century, we began to better understand how wildfires play such vital roles in shaping our Mediterranean ecosystems and landscapes. We reluctantly acknowledged that they must occasionally and necessarily revisit our grasslands, woodlands, and even some forests, and how Native Americans, for thousands of years, encouraged fire’s eminence with their control burns. Until the late 1900s, much of the timber industry and some environmentalists ignored these realities, especially in our most cherished forests that include ancient redwoods. After all, forest fires can destroy beautiful trees and valuable timber destined to become forest products. The infernos kill precious wildlife and leave ugly open scars and charred landscapes that remind us of fire’s terror, death, and destruction. But we now better understand how, even in our redwood forests, wildfires establish delicate successional cycles, balances that must be maintained if California’s ecosystems are to survive and prosper.        

We can’t be blamed for the obsessive love we have shown for what remains of redwoods that weren’t cut down and sent to the mills. (Less than 5% of our old-growth coast redwood forests were spared from the saws.) California’s two redwood species represent the largest and tallest trees on Earth. On the surface, these majestic forests appear to be the last places where you would expect, much less want, to see a fire. So, we did our best to keep fire away from these stately behemoths that can grow to more than 2,000 years old. But it was fire suppression and other human interference (such as the introduction of volatile nonnatives) that set the stage for recent unprecedented conflagrations in California forests. The megadrought that extended through the first two decades of this century (enhanced by climate change on steroids) provided the blowtorch on landscapes with abundant accumulated fuel to burn. Scientists and nature lovers looked on in horror and then heartbreak as many of our ancient redwood forests were incinerated.

The largest, hottest, and most destructive wildfires in California history swept through from 2015-2021. But the long-term effects of these intense burns in our redwood forests have been quite different, depending on the contrasting species and plant communities: Giant Sequoias (Sequoiadendron giganteum) along the western slopes of the Sierra Nevada and Coast Redwoods (Sequoia sempervirens) along the north coast fog belt.

As winter storms drift off the Pacific and encounter the Sierra Nevada, air is forced to rise up western slopes, where it cools and condenses, dropping abundant orographic precipitation. Heavy snows are common, which gradually melt into the deep sandy soils as spring advances toward summer. Giant sequoias rely on this meltwater into the summer drought. Occasional summer thunderstorms might also briefly interrupt the seasonal droughts, but they are not such reliable sources of water. However, those summer storms also produce lightning that ignites fires in Sierra Nevada forests, producing a fire season that peaks during the hotter summers and often lingers until the first early winter-season storms can douse them.

Following decades of fire suppression and accumulating fuels since the 1800s, and the introduction and invasion of highly combustible nonnative grasses and other species, a devastating megadrought plagued California. It started around 2000 and lasted for more than two decades. (These weather patterns and their impacts have been highlighted in multiple stories on this website and in my new book, The California Sky Watcher.) Though this historic dry period was punctuated by a few brief wet episodes and floods fueled by powerful atmospheric rivers, gradually warming temperatures and extreme summer heat waves quickly evaporated water out of our ecosystems and into the atmosphere with increasing vapor pressure deficits. Weather stations across the state repeatedly recorded their hottest days, months, and seasons, breaking all-time records. Bark beetles and other opportunists exploited the moment, further weakening native species and ecosystems already under stress.  

From 2015-2021, at least six major fires raged through 85% of Sierra Nevada’s giant sequoia groves. The most destructive was the Castle Fire in August 2020, which killed 7,500-10,600 giant sequoias or about 10-15% of all Sequoiadendron giganteum on Earth. In September, 2021, the Complex Fire killed 1,300-2,400 giants and the Windy Fire destroyed another 900-1,300 of our cherished ancients that can grow up to 3,000 years old. All three named wildfires were ignited by lightning. By the end of 2021, nearly 20% of all giant sequoias had burned to death within only seven years. And now, it is feared that denuded ecosystems and other stresses could kill more fire-ravaged trees as we witness delayed mortality rates. I remember watching Christy Brigham (Chief of Resources Management and Science at Kings and Sequoia National Parks) on national network TV, as the media interviewed her in their stories about the devastating fires. Years earlier, Christy had worked with my students, helping to guide my field classes into her research. Fast forward and there she was again, the celebrity ranger and scientist under the Sequoias, attempting to educate a national audience about the importance of managing our forests and limiting climate change so that we might save what unique and precious resources remain.                       

We have learned how our giant sequoia forests, like other California plant communities, thrive with occasional wildfires. Older, tall sequoias have thick, fibrous, fire-resistant bark and they drop lower limbs as they grow so that fires can’t leap up from below into their towering crowns. Heat from the fires below encourages seed dispersal into recently-cleared soils. Over the millennia, these forest floors were regularly cleared by occasional ground fires that consumed accumulated fuels and took out smaller trees before they could act as chimneys to guide the flames higher. After more than a century of fire suppression, we realized our mistakes. But when the megadrought hit, it was already too late and it will take decades to reverse these trends that humans have set in motion. And so, the ancient giants burn and die.

Moving to the Coast

Coast redwoods (Sequoia sempervirens) also benefit from heavy orographic precipitation (up to 100 inches/yr.) that falls when winter storms sweep off the Pacific and encounter coastal slopes. But snow is rare in these moist and cool, but milder climates. Instead, these forests remain damp through most of the summer drought season by catching coastal fog that drifts off the Pacific with the cool sea breeze and then drips down to the forest floor. Since these thick, shady forests appear relatively green and lush throughout the year, and they hold some the greatest biomass of any California terrestrial plant community, it is more difficult to imagine how fires could be such important players. But they are, especially after drought years capped by hot summers.

This is exactly what happened in August of 2020, when yet another summer heatwave sucked remaining precious moisture out of the redwood forests near the end of the megadrought. A series of thunderstorms with dry lightning drifted across California, igniting wildfires in already parched plant communities. The August lightning teamed up with the ongoing megadrought to make 2020 the worst wildfire year in state history. Nearly 10,000 fires burned over 4.4 million acres (about 4% of the entire state).

Multiple ignitions grew into three blazes that combined to form the CZU Lightning Complex Fire, which ripped through nearly all of Big Basin Redwoods State Park, including some of the most beloved coast redwood groves. As pictures filtered through the media, public shock turned to heartbreak. Intense, hot fires feeding off accumulated dry fuels sent flames high into the sky and into the canopy, torching magnificent coast redwoods that had stood for more than 1,000 years. Park headquarters, visitor centers, and other infrastructure turned to ashes. Everything in our cherished forest, where I had sought refuge decades earlier to admire and learn from the wonders of awesome nature, was burned to a crisp. Beloved Big Basin, home to the most southerly extent of our largest old-growth coast redwood groves, accessible to millions of city dwellers in the Bay Area, and treasured by millions of others in and beyond California, was gone. Or, was it?

Here is where the two fire stories diverge as we recognize even more glaring contrasts between the Golden State’s two redwood species and their plant communities. In the links that follow this story, you will see a Big Basin that appears to be burning to the ground. But new redwood growth appeared within weeks after the conflagration, such as basal burl sprouts and sprouts from tree trunks. Decades of carbon storage emerged to the surface as fresh green shoots. And by the time I returned to my cherished sanctuary, recovery and natural regeneration was evident everywhere, only four years after the inferno.

Though the firestorm killed understory species and most Douglas firs, nearly every scorched redwood was sprouting, evolving from snag tress that began to resemble bottlebrush trees. Not only were sprouts emerging from the base of the trees, but charred limbs were being covered with fresh, fuzzy green growth. This is not to understate the damage that had been done. It will take generations for these forests to recover. More xeric chaparral (such as ceanothus) and ecotone species had invaded open spaces that had previously been cool, moist, shaded enclosures sheltered by a redwood canopy. Invasive weeds included crowding opportunists such as French broom and yellow star thistle. Much of the former forest floor was now exposed to intense direct sunlight, encouraging sun-loving invaders that can withstand large daily and annual temperature swings. Exposed creeks and streams ran much warmer in the summer and carried high sediment yields during the winter rainy season. Just before I arrived in 2024, local air temperatures soared over 100°F during an early July heatwave. But the seared coast redwoods somehow survived it all, and a rich diversity of flora and fauna was returning and evolving in a fantastical story of rebirth. Birds and other wildlife, such as raccoon, fox, deer, coyote, and mountain lion were finding homes within the recovering diversity of habitats.

The two contrasting redwood fire regimes in this story leave us with plenty of science lessons about the natural systems and cycles that nurture such forests. As you might expect, these burnt landscapes are attracting researchers from around the world. They include scholars from the Stephens Fire Science Laboratory, the California Fire Science Consortium, and the UC Center for Fire Research and Outreach. The following are just a few summarizing thoughts.

Our most diverse forests represent more resilient plant communities capable of adapting to gradual and sudden extreme changes. Occasional cool fires encourage a diversity of habitats and plant species, which support more diverse animal species, ranging from bees and other insects to much larger predator and prey. By contrast, aggressive fire suppression leads to stagnation and homogeneity, which could lead to the demise of species and entire ecosystems. Likewise, if hot fires reoccur too frequently, introduced grasses and other invasive fire-loving species could encourage even more frequent fires that alter ecosystems. If you think this suggests a delicate and complicated balance, you nailed it. For centuries, most California ecosystems adjusted to relatively cool fires with spotty hot flareups; redwood forests had adjusted to high fire complexities with a large variety of burns that may have returned every 6-35 years or so. Suppressing such fires disrupts natural succession. However, super-hot, frequent fires everywhere can also disrupt natural cycles, leading to decreasing species diversity and ecosystems less resilient to changes that can destroy them. During the last two centuries, humans have interfered with these natural cycles, which has encouraged high fire intensities and severities capable of searing nearly everything in the forest.

In the bigger picture, there are many more examples of how humans have directly impacted California’s natural fire cycles. The most dramatic changes can usually be found in what has gained a most descriptive and popular name: the wildland-urban interface (WUI). We can’t allow wildfires to destroy billions of dollars in property and kill people as they sweep into our communities, so we try to stop them at our fabricated boundaries. But what is considered defensible space is negotiable in a fire regime where burning embers can be blown over a mile from the active front by high winds. These dilemmas become particularly evident as we encroach further into nature and extend our human footprints. How can we ever restore natural fire cycles when we inevitably find ourselves living adjacent to the very natural landscapes we wish to preserve?

Human impacts on particular keystone species have also changed our fire cycles. As just one example, wildlife officials are working to reintroduce the North American Beaver (Castor canadensis) into select waterways across the state. This keystone species is now considered an ecosystem engineer that expands diverse habitats that then increase and improve nature-based ecosystem services. Beaver dams and ponds widen water courses and raise water tables to irrigate larger, lusher, more diverse and productive riparian habitats and gallery forests. Wildfire behaviors change drastically when they approach such wider, well-watered green barriers. Imagine the countless other ways that assisted natural regeneration can increase ecosystem functionality after a forest fire and help reboot our wildlands back toward their natural fire cycles.

I’ve been walking into and gazing up to these magnificent wonders-of-our-world forests to admire and study giant sequoias and coast redwoods for five decades, assuming they would outlive me. I and some of my field students sensed the changes over time. During my next visit, I wonder if these venerable towering elders will be poking fun at me for thinking five decades is a long time. Only now, I must also wonder which of us might be first to decompose into the dust of future generations.  

Still looking for more? Check out the following rather exhaustive list of articles and videos summarizing recent research in California’s redwood forests. There is plenty to unpack here, but you are rewarded by hearing and learning from the experts. Following the links, join me again as I take you on more lengthy self-guided photo tours through these forests.

The first three links are to stories on our website (that now date back several years) highlighting California’s wildfires and/or redwood forests. You can also surf through our website to find multiple stories about weather patterns and climate change. Next is the list of articles and videos from the forests. The final links take you to the most recent researchers using geospatial technologies to help us understand how species are adapting to these changes.  

The Wildfires of 2020:

Forest management and research and perspectives from of one of my former students working in the redwoods:

Encountering coast redwoods with colleagues on a field trip in northwestern California:  

Sequoia and Kings Canyon National Parks Research Projects

Fire Reoccurrence in the Sequoias

Good Article about Sequoias and Fire, with Video, from Outdoor Magazine

Save the Redwoods League

Here is an old NPS article describing the redwoods.

NPS on the Sequoia Fires 2015-2021

NPS on Giant Sequoias and Fire

Castle Fire Research Video from Scientific American

The following three articles focus on Big Basin:

Fire recovery survey, April, 2022, written by Biologist Steve Singer

Fire Recovery in Big Basin

Save the Redwoods League Article Summarizing Recovery at Big Basin

More on California’s Coastal Redwoods:

Nature Plants Article on Regrowth in Coastal Redwoods

Indigenous tribes rekindle control burning in northwest California forests.

Northwestern California Karuk and Yurok tribes revitalize cultural burning.

If you can navigate through the commercials, “It’s History” recalls what happened to most of our coast redwoods.

Do you want to dig deeper into recent related research projects? It turns out that California has become a laboratory for using cutting-edge geospatial technologies to map our evolving plant communities and their thousands of species. Scientists and citizens are using these new technologies to track species as they adapt to climate change, fire, and a host of human impacts. Check out these links, but give yourself some time if it’s all new to you:  

The summary sent from Bill Bowen

The PNAS Article

You could start here if iNaturalist is new to you.

Evolutionary adaptation of species to climate change at the MOILAB

For you more curious and adventurous folks, the following photo essays take you through several of our redwood forests. These colorful tours represent a lifetime (decades) of adventures, field trips, and research projects in California’s redwoods. I used some of the signage in each park to take the place of captions and to give you the sense that you are walking with me. You may notice that no photos were manipulated. Here’s your chance to lose yourself and learn from the forest. Click on each page to walk through a different region.          

The post Fire in the Redwoods first appeared on Rediscovering the Golden State.

It’s invisible, underestimated, misunderstood, and often taken for granted. It transports and directs air masses, storms, moisture, clouds, smoke, dust, and sand. It glides over ocean and lake surfaces, generating waves (see our earlier website story about waves). It spreads pollen that helps propagate plant species and carries odors that animals must follow for survival. Insects, birds, and planes must fly into and through it. It can set the day’s moods: refreshing here, maddening there. It can nurture life and then destroy it in an instant. We could never give wind enough credit for rocking our world. No wonder we have assigned such colorful and descriptive names to winds common to Californians: Diablo, Santa Ana, Sundowner, Mono, Washoe Zephyr, Sierra Wave, Palmdale Wave, etc. … and even shared their stories on our website and in our book. The wind keeps us guessing with its wild mood swings and leaves us on the edges of our seats with its entertaining performances: swirling, dancing, rustling, whispering, singing, moaning, and howling, And then it vanishes and gives us the silent treatment.

How fast can winds blow across the Golden State? Recent records have been set, thanks to increasing wind speeds and our improved technologies to measure them. It is not surprising that records fall when strong currents are forced to skim over the state’s highest ridges and peaks, mostly in the Sierra Nevada. During the powerful atmospheric river that swept the state on February 4-5, 2024 (see our recent website story), a 162-mph gust was recorded at Ward Mountain (8,643 feet asl), above the Tahoe Basin. During the same storm, a 148-mph gust blasted across nearby Palisades Tahoe (8,700 ft) while a 125-mph gale roared past Mammoth Mountain. This was part of a massive and destructive windstorm that ravaged Northern California from the coast to the mountains, knocking out power to nearly one million people. Just weeks later, on March 1, 2024, a 190-mph gust swirled over Palisades Tahoe during the historic blizzard that is summarized in this story with weather maps. But none of these have yet eclipsed the NWS official 199-mph confirmed record set at Ward Mountain Palisades in 2017. Several records over 150-mph have been set on other peaks and ridges, but those above 8,000 feet looking down on the Tahoe Basin are the consistent Golden State winners. (California wind records can’t compete with the US wind speed winner: Mt Washington in New Hampshire at 231-mph.)        

We all share memories of how windstorms interrupted or changed our lives when the gusts reshaped landscapes and damaged infrastructures around the places we call home. My mountain neighbor Steve Chadwick, who also spent ample time living in the desert, reminds me how windstorms occasionally blow sand across Coachella Valley roads. He and other residents have watched several desert roads (Gene Autry Trail and Indian Canyon Drive are examples) disappear below the shifting sands. After each event, the buried roads-turned sand dunes must be closed until sand plows (think snow plows) clear the way. Up on the nearby mountain around Idyllwild, power is interrupted when windstorms knock branches and trees down on to utility lines. Today, power companies across California are busy year-round clearing branches and dead trees away from their lines that may threaten to ignite the next deadly wildfire. Still, life on Earth requires wind and Steve was also quick to remind me how tons of dust blown from the Sahara are essential to the health of the Amazon. Here is a fascinating NASA article that summarizes this discovery.       

The big wind show starts with a pressure gradient force. Because wind always wants to blow from relatively high atmospheric pressure to low pressure (at the same altitude above sea level), air flows. The breeze or wind you sense is the force of billions of air molecules per cubic centimeter racing out of high pressure and into low pressure systems. When strong high- and low-pressure systems are positioned very close to one another, there is a steeper pressure gradient that will energize stronger winds. By contrast, when there is little or no difference between high and low air pressure around you, the wind will remain calm. Since pressure systems are constantly strengthening or weakening and migrating, wind velocities are always changing. The billions of air molecules you feel and breathe have likely traveled thousands of horizontal miles and thousands of vertical feet (or meters) to get to you. They are sailing messengers announcing how our dynamic atmosphere is fluctuating and what changes you might expect in the future.

Because Earth turns under this air set in motion, the Coriolis effect will also kick in. The wind will be turned to its right out of high-pressure systems in the northern hemisphere and also nudged to its right as it flows into low-pressure systems. Add friction near Earth’s surface and the pressure gradient force will gradually win this windy tug-of-war. This is why winds spin clockwise out of high pressure anticyclones (fair weather systems) and counterclockwise into our northern hemisphere low pressure cyclones or storm systems. (Note that winds turn and spin in opposite directions when pouring out of highs and into low pressure systems in the southern hemisphere.) Looking for more details about these pressure patterns and winds? Check out the weather maps at the end of this story and then our new California Sky Watcher publication.

There is much more to this aeolian story, but you can see why spring can be a breezy season. Extreme temperature gradients can bolster strong pressure gradients as warm summer air masses encroach upon winter’s stubborn cold air masses. Sporadically and unevenly, summer will win this annual war, but not without some windy battles. Additionally, as the longer days and higher sun angles rapidly warm inland land surfaces, the progression through spring encourages onshore breezes. Air will begin expanding and rising above those heated land surfaces, creating thermal low pressure there that will suck in the cooler, denser air that forms above our cold ocean currents. Sea breezes and their marine layers will begin to dominate weather conditions along the coast well into summer. Mountain barriers represent massive blockades, except for the few canyons and passes that become narrow wind tunnels where coastal air masses attempt to squeeze inland. You will find some of our largest wind turbines – producing energy for millions of Californians ­– aligned within these natural air vents.            

Continue with this developing photo essay as we demonstrate how wind shapes our world and how we can estimate wind direction and speed by looking up at the sky. We highlight some of the windiest episodes that ended the winter and continued into the spring of 2024. Conditions became particularly exciting at the end of this wet and stormy El Niño season, which threatened to complete the wettest two consecutive years in Los Angeles history. If you are looking for more detailed meteorological explanations for all this air pressure and wind mania, continue to the final weather maps near the end of this story.            

The wayward wind might be a restless wind, but it opens windows for us to sense the systems and cycles that rule in our natural world, beckoning us to explore and better understand the vital scientific experiments that nature conducts every minute of every day. Because we have just swirled around the edges of such a tempestuous topic during this brief summary, you might want to check out a new publication where we blow the lid off the many aeolian mysteries found on our third rock from the sun: California Sky Watcher.

The post Blowin’ in the Wind first appeared on Rediscovering the Golden State.

Whether they are considered nature’s great cathedrals or breathtaking scenery without rivals, there is nothing quite like them on this planet. They helped inspire me and millions of others to learn more about the natural forces and processes that are shaping our world and how we all fit in. They and other grand landscapes in California and beyond motivated me to become the student, researcher, teacher, and naturalist that I am today. We have featured Yosemite Valley and Kings Canyon landscapes in previous stories that you will find in this project and website. In this story, we explore Zion Canyon.

How has it changed and how does this high desert canyon compare to and contrast with our Yosemite? Join me, your master ranger and natural history interpreter armed with 50 years of observations and field experiences, as I guide you to discover the science behind the scenery.

On the surface, there are some uncanny similarities between our Sierra Nevada’s Yosemite and Utah’s Zion. Each of these valleys sits at about 4,000 feet (1,200 m) above sea level, surrounded by thousands of feet of vertical rock walls soaring abruptly above their eroding rivers. Each of their names begin with the last letters of our alphabet, monikers that recall the people and cultures who once settled in these other-worldly canyons. But great differences stand out when we look a little closer.     

We returned to Zion’s campgrounds during the prolonged and historic heat wave of July 2023, a month when the high temperature at their weather station (near their Human History Museum and Visitor Center) made it to 110° F (43° C) on two days. Only four days of that month had high temperatures just below 100° F (38° C), which is closer to the July average. (The highest temperature ever recorded at Zion was 115°, including July 10 and 11, 2021.) This contrasts with their typically lowest temperatures in the teens over the winter and a low of 14° F (-10° C) on January 31, 2023.

Imagine experiencing such a 124° temperature range in one location within less than six months! Welcome to cold winters and hot summers common to the thin dry continental air of the high desert. During this trip, nature forced us to alter our daily schedule so that we could hike the dry trails during early mornings and evenings and spend the hottest afternoons within the shaded narrows, immersed in the Virgin River, or at the museum or visitor center. We were rewarded with comfortable evenings to view bats darting around and then thousands of stars rotating in the dark night sky.

Weather patterns and climates in Zion are glaringly different from our Yosemite, which drains and opens toward the west, facing the Pacific Ocean. As wet winter storms stream off the Pacific, they dump copious amounts of orographic rain and snow as they glide up Sierra Nevada’s western slopes. (Check out our earlier story on the atmospheric rivers of 2023 and an even earlier story following a water drop.) Yosemite Valley averages more than 36 inches (>91 cm) of precipitation per year and the surrounding high country receives even more.

But by the time those Pacific storms skim over southern Utah’s high desert, they are usually spent, leaving only trace amounts of precipitation. Zion Canyon averages only 15.7 inches (40 cm) of precipitation and 3.8 inches (10 cm) of snow each year, compared to the massive snow drifts that accumulate in the Sierra Nevada each season. Also in contrast to our Yosemite and Kings, Zion has a distinct late summer rainy season associated with the Southwest (North American) monsoon, averaging more than an inch of rain each month from July through October. And though Yosemite may briefly be dampened by infrequent isolated summer storms, such quick hitters are not reliable precipitation producers or drought busters in what John Muir coined our Range of Light.

Torrential summer rains soaked Zion and the Desert Southwest in 2022, causing extensive flash flooding. But the North American monsoon did not perform during our visit on this sizzling July of 2023. Only 0.05 inches was recorded on the only day of precipitation that month (July 25). The fickle monsoon thunderstorm cloudbursts and flash floods will repeatedly wash out roads and trails and carry people away in the debris during one summer and then be disappointing no shows the next. Plants and animals and people who have not adapted to these high desert weather extreme realities do not survive. There is even a late summer rainy season flowering cycle on exhibit in the Southwest and across the Colorado Plateau. This is also why, when cumulus clouds begin boiling into thunderheads within the thermals that rise in summer’s midday heat, we are warned to steer clear of Zion’s narrows and slot canyons that can become violent cascading death traps within minutes. You can thank these powerful gully washers for helping to carve the deep canyons such as Zion that have made Colorado Plateau scenery world famous. In contrast, Yosemite’s Merced River and other Sierra Nevada streams and their ability to erode and deposit are dependent on runoff and snowmelt from those winter storms off the Pacific.

The Sierra Nevada and Colorado Plateau are composed of very different rock formations lifted by very different tectonic forces. The core of Yosemite and the Sierra Nevada is mostly made of massive granitic batholiths that cooled and crystalized from gargantuan underground magma chambers formed in subduction zones around 100 million years ago. More recent vertical faulting has elevated their solid granitic escarpments along steep eastern slopes until high Sierra Nevada peaks reach more than 14,000 feet (4,267 m) above sea level, while western slopes more gradually descend toward the Great Central Valley.

In contrast, the Colorado Plateau is underlain by thousands of feet of mostly sedimentary deposits that also date back more than 100 million years. Millions more years later, heat, pressure, and nature’s glues had lithified the particles into sedimentary rocks. The relatively undisturbed layers were more recently and gradually warped upward by compressional forces until the highest points of the plateau soar over 12,000 feet (>3,658 m) ASL. Gravity’s pull on water flowing from such lofty elevations has energized streams to cut deep canyons into Sierra Nevada’s granitic plutons and into the Colorado Plateau’s vulnerable layers of sedimentary rock formations.

The Grand Canyon is often used as the classic example of how a powerful river (the Colorado) can erode deep chasms as surrounding landscapes are lifted higher. Weathering and erosion will eventually widen the incised narrows over time. The relatively young Zion Canyon is also widening as the Virgin River cuts through it.  

Yosemite and other Sierra Nevada canyons have been carved by floods from wet winter storms and snowmelt that runs off impressive snow packs well into the summer. But the most spectacular high country Sierra Nevada valleys and canyons were also extensively carved by alpine (mountain/valley) glaciers during previous glacial periods. As the flowing ice scraped out deep high-elevation cirques and U-shaped trenches through preexisting mountain canyons, glacial moraine rock piles were deposited downstream, leaving dramatic Ice Age landscapes. (Check out our webpage story from 2019, Norway vs. California, where we examine such glacial grandeur.)

Today’s summer storms contribute relatively little runoff into today’s Sierra Nevada streams that follow those canyons. On the Colorado Plateau, gentler cold winter rains and melting winter snows also add to frigid runoff into the canyons. And like Sierra Nevada rock formations, cycles of freezing and thawing during winter help to crack and physically weather rocks so that blocks are liberated to break off from the cliffs and eventually be carried away after they disintegrate into smaller pieces. But summer’s violent flash floods are responsible for transporting much of that loose rock and sediment downstream in Zion. And only the highest peaks and ridges of the Colorado Plateau exhibit some glacial topography; Zion Canyon and Desert Southwest landscapes were not carved by powerful Ice Age glaciers such as those that once scraped through Sierra Nevada high country.  

There are also glaring differences between Yosemite and Zion in the color and texture of their rock walls. The granitic rocks of the Sierra Nevada are dominated by lighter minerals of quartz and feldspar, but are often speckled with darker crystals containing more iron and other heavier elements. This massive stew of magma chamber chemicals solidified into a solid salt-and-pepper matrix of rocks and minerals.

As the mountains were lifted, overlying rocks were weathered and stripped away, exposing them to weathering and erosion. Chemical weathering processes can be seen as dark stains and vertical streaks on the cliffs where iron and other darker elements oxidize in the water and air. Physical weathering processes include exfoliation, the pressure release that breaks massive rocks into thin skins or onion-like layers to slide and fall downslope. (Check out our website story where we follow a grain of sand.)

In contrast, the sedimentary layers of Zion are clearly and classically stacked with the older deposits on the bottom and the younger rock formations on top of them. (Still younger rocks that once capped them have been eroded and washed away long ago.) Click here for more rock layer details. The Virgin River has sliced through all of them like a sharp knife through a layer cake: nature’s road cuts. Relatively resistant lighter-colored sandstones are dominated by sandy grains with more quartz and feldspar. The layers grading from sandstones to siltstones and mudstones and shales that contain more iron and other heavier elements tend to oxidize into rusty and red colors when exposed to air and water; thinner skins of these weathered surfaces are sometimes referred to as desert varnish. And so, the highly-resistant lighter-colored speckled cliffs and canyons of the Sierra Nevada look quite different from the thousands of feet of vermilion layers of sedimentary rocks weathering in Zion. In both cases, millions of years of internal mountain building forces and external denudational processes have conspired to sculpt some of the most spectacular landscapes on Earth.

Contrasts between our Sierra Nevada and the Colorado Plateau (and particularly Yosemite and Zion) are also noticeable within their plant and animal communities. In both regions, you can find the classic vegetation zones grading from Lower Sonoran grasslands and prairies to Upper Sonoran chaparral and open woodlands, to Transition Zone woodlands and open forests, to Canadian Zone cooler and wetter forests, to still loftier subalpine Hudsonian plant communities, into the highest Arctic-Alpine Zone islands. But wetter Sierra Nevada slopes nurture lusher forests with species such as Giant Sequoias (Sequoiadendron gianteum, the largest trees on Earth) that you won’t find on the drier Colorado Plateau.

So, as you climb up from lower elevations in Zion toward higher elevations on the Colorado Plateau, you will notice high desert xeric species. They include Rabbitbrush (Ericameria nauseosa), Big Basin Sagebrush (Artemesia tridentata), and several different species of buckwheat. A little higher up, you will find what some call pygmy woodlands. Pinyon pines (Pinus monophylla and Pinus edulis) grow with live oaks and other oak species that shed their leaves, growing from shrubs into small trees. They mix with Utah Juniper (Juniperus osteosperma) at lower elevations around 4,000-5,500 feet in the Upper Sonoran and Red Cedar (Juniperus scopulorum) at higher elevations above 5,000 feet in Transition and Canadian Zones. Ponderosa Pines (Pinus ponderosa) appear and grow denser at higher elevations as we make our way into wetter mixed conifer and aspen forests with Douglas Fir (Pseudotauga menziesii), White Fir (Abies concolor), White Pine (Pinus strobiformus), and Quaking Aspen (Populus tremuloides). You also will find a host of colorful wildflowers decorating the understories at these higher elevations. Several species bloom throughout the summer, nurtured by those monsoon thundershowers that more commonly soak the cooler high plateau.

As with riparian communities in the Sierra Nevada, biomass and species diversity dramatically increase along and adjacent to stream and river courses. Where soils remain damp and the relative humidity increases around water courses in Zion, look for denser stands of Fremont Cottonwood (Populus fremontii), Red Birch (Betula occidentalis), various willow species, cattails, and rushes. As you enter the narrows where natural springs and seeps erupt from the sandstone cliff faces, look for fern and other water-loving species that combine in rock cracks to form delicate hanging gardens. Water might also be king in California, but life-giving moisture can transform Colorado Plateau’s dehydrated high desert into productive ecosystems that support numerous species of plants and animals.

Zion’s birds share the advantage of flying to water and food sources. We spotted some raptors, roadrunners, ravens, turkey vultures, and a condor flying overhead. But the real flying shows in Zion start just after sunset, when a seemingly chaotic air show of bats dart around, using their sophisticated radar to hunt and keep insect populations under control. You will also find the greatest number of species and densest populations of animals around Zion’s water courses. We saw wild turkeys, mule deer, and fox in the canyon. Raccoons, skunks, bobcats, porcupines, and owls are also found in the riparian habitats near water, mostly at night. Coyote can be heard howling around the canyon as they hunt in the twilight and darkness. Though American Beavers (Castor Canadensis) have burrowed their lodges into the banks of the Virgin River, they are difficult to spot. They don’t build beaver dams seen along other western rivers, since the river-altering structures would be destroyed by frequent flash floods. Look for the chewing scars on cottonwood trees near the river. All of this gnawing and other beaver activity usually peak during overnight hours, when it is more difficult for predators to hunt them.

As with Yosemite, humans have impacted Zion mammals and cut predator populations in the canyon. There are only a few cougars in the entire park. Such extermination and displacement of mountain lions by early farmers and ranchers and then crowds of visitors caused an unnatural explosion of deer populations. These ubiquitous browsers then feed on cottonwood and other seedlings to reduce the normal rate of plant regrowth. The results include decreasing biodiversity and increasing impacts on populations of many different riparian species. Add efforts to control reoccurring flood damage and you can see how natural channel flow has been destabilized along the Virgin River. This is another classic example of how human impacts can become ripple effects that can change natural systems and cycles and then entire landscapes, even in our national parks.

And that brings us full circle to what Yosemite and Zion might have most in common: they are perfect examples of unique landscapes of grandeur and national parks that we are loving to death. Yosemite is just about 200 miles (or four hours) from Bay Area cities, just over two hours from Central Valley population centers, and about 300 miles (6 hours) from LA. Generations of traditional Yosemite National Park lovers live in these California conurbations. Zion is only about 160 miles (2.5 hours) from a growing Las Vegas. Each of these nearby major metropolitan areas welcomes millions of tourists each year and many of these visitors clamor to squeeze a visit to one of these iconic parks into their itineraries. Unlike those of us who adore our national parks as places to find peace and solitude and to experience and learn about nature, the average visitor spends only a few hours on the ground in those national parks. Millions of people each year exploit them as social media selfie checkoff lists.

The crowds began choking Yosemite Valley decades ago, especially on summer weekends. They brought massive traffic jams, pollution, chaos, and amusement park atmospheres in what were supposed to be exceptional natural environments to be cherished and preserved for the benefit of future generations. Yosemite experimented with reservation systems from 2020-21 and a peak hours reservations system in 2022. Park officials are currently using data gathered from these experiments to develop a Visitor Access Management Plan and you are invited to provide your input. Avid naturalists and backcountry hikers have also been impacted, with most backcountry trails and wilderness areas requiring permits. Growing crowds traipsing to the top of Half Dome (a round-trip hike of about 15 miles with a 4,800-foot elevation gain) eventually created dangerous and sometimes deadly conditions on the steep and slippery dome. I’ve trudged to the top a few times over the years, but today’s permit system limits 300 hikers per day to make use of the chains and steps that lead up the side of the dome.  

Zion National Park is challenged with similar dilemmas: how do our most beloved and popular parks offer access to the greatest number of people, without ruining the nature experience for each visitor and compromising the mission and integrity of our national parks?

Several years ago, Zion’s crowds multiplied as nearby Las Vegas grew and the Utah Office of Tourism began promotions to attract visitors from other states and from around the world. It worked too well if you enjoyed Zion for its nature experiences. The summer traffic and crowds in the canyon became so chaotic, the park was forced to close the road into the canyon to vehicles and require visitors to take the free shuttle from early spring into late fall. Another amusement park atmosphere erupted especially on summer weekends as overwhelmed tourists jammed the overwhelmed visitor center. Others were herded through the maze of winding chains that eventually led them into shuttles where they were crammed like sardines, hoping to eventually be dropped off at key stops to search for their elusive solitude. Add some stifling summer heat and you can see why rangers who wanted to interpret and share the beauty and magic of nature have been forced into crowd control that sometimes turns into safety concerns and crime control after visitors reach their boiling points; good for the businesses in adjacent Springdale, not so good for anyone seeking a quiet nature experience.

And as if to mimic Yosemite’s Half Dome, the narrow chain path up to Angel’s Landing finally got so popular, it turned into a dangerous line of frustrated climbers scrambling over one another. And so, similar to Half Dome, the National Park Service has been stringently enforcing their Angels Landing Pilot Permit Program. I’ve also meandered up the steep switchbacks to this popular peak a few times in past decades, but don’t attempt these memorable climbs without your permit these days.

Whether there are too many people searching for their peace and quiet in nature, or too many people searching for their perfect selfies to post on social media, I don’t offer any better solutions to the crowd control problems that have plagued these otherwise magical wonderlands during recent years. I do know that our world has changed since we could roll in and get first-come, first-served camping spots during the summer in our most spectacular national parks. And I wish the folks at the National Park Service the very best as they struggle to balance the often conflicting serve and preserve missions.

For your part, it is best to visit these magnificent gems off season during weekdays when possible. Or, you can find your solitude at nearby less popular and more remote natural sanctuaries; there are still plenty to choose from that can be just as rewarding and many have been highlighted in stories on this website. In California, some of these retreats are closer to home and more easily accessible than you might think.

If you have a little more time, come along on the following bonus trip. Let’s move up to the plateau more than 3,400 feet (>1036 m) above the canyon along what is called the West Rim Trail to see how the biogeography at higher elevations around Zion National Park is so different from the hotter and drier deserts below. We will leave the crowds behind and then leave you on the high plateau above 7,000 feet (>2,130 m) in the Zion wilderness where summers are delightfully cool (if you can avoid the occasional thunderstorms) and winters are icy cold. For those looking for an introduction to Zion from the National Park Service, check out the link at the end of our story.

Before you go, visit the official National Park Service website that will help you prepare for your adventures: https://www.nps.gov/zion/index.htm

The post Zion vs Yosemite: the Science behind the Splendor first appeared on Rediscovering the Golden State.

Follow this series of NOAA maps from August 16, four days before landfall:

It all started several long days before Hilary’s August 20 landfall, when the National Weather Service recognized yet another band of showers and thunderstorms forming off Mexico’s southwestern coast. Models forecast favorable conditions (including warm ocean water temperatures) supporting the rapid development of a tropical cyclone that would likely become a major hurricane. And this one would be different. Longer-term models suggested that the strengthening storm would drift northwest and up along the Baja coast toward southern California. Days later, by Thursday, August 17, the National Weather Service was already warning us about Hilary, which was churning over the warm waters south of Baja. Here is an excerpt from the Forecast Discussion issued by the National Weather Service on that afternoon, still three days before the storm swept through:

National Weather Service in San Diego at 152 PM PDT Thu Aug 17 2023:
“Hurricane Hilary will continue to progress north off the coast of Baja, bringing widespread rain and the potential for flash
flooding across Southern California late Saturday through Monday.”
AND…
“Hurricane Hilary is expected to rapidly intensify as it moves northward up Baja
California, then weakening as it hits colder waters in northern
Baja.”
AND…
“Regardless of the exact track and intensity of Hilary, which 
could continue to change in the coming days, it will bring a 
substantial surge in moisture into Southern California, with heavy
rainfall and a high potential for flash flooding, especially for 
the mountains and deserts. A Flood Watch has been issued with the
afternoon forecast package for all areas Saturday through Monday.”
AND…
“Current forecast rainfall amounts Saturday through Monday:
Coast: 2 to 2.50 inches 
Valleys: 2.50 to 3 inches 
Mojave Desert: 3 to 4.50 inches 
San Bernardino County Mtns: 4 to 6 inches, locally up to 8 inches
on the eastern slopes
Riverside and San Diego County Mtns: 4 to 8 inches, locally up to
10 inches on the eastern slopes 
Lower Deserts: 5 to 6 inches”

Follow these NOAA images from August 17:

Fears of damaging coastal winds and a possible storm surge would never be realized in California since it came ashore south of the border. However, final rain totals would confirm NWS predictions. By Friday, August 18, as predicted, Hilary was already a major Category 4 hurricane, but why were forecasters so confident that it would be steered toward the north-northwest and into southern California within just two days? We can partially blame that humongous, stubborn, and equally historic high pressure system that wobbled and expanded above the southern U.S., producing record high temperatures that tortured Texans and surrounding regions through most of the summer. Winds circulating clockwise from it were streaming from south to north over the southwestern U.S., on the far western edge of that high. These southerly winds were further enhanced by another unseasonably stubborn system: low pressure sitting just off the California coast. As winds were spinning counterclockwise into that low, southern California was positioned on its southeast edge, further encouraging winds to stream over us from the south and southwest. Sandwiched between these two pressure systems, southern California was located below an upper air high-velocity freeway, a perfect conduit that would rapidly push Hilary up the Baja coast and toward us.    

Follow this series of NOAA images from August 18:

Those strong winds would also mold Hilary and change her behavior and impacts as she grew closer. First, the storm started moving very fast; unlike most other tropical cyclones, there was little time for it to completely dissipate as it raced over our colder waters that quickly kill most hurricanes. (Recall that tropical cyclones, powered by latent heat of condensation, require ocean water temperatures near 80° F (27° C) to develop and remain strong.) This made it likely that it would make landfall and then sprint into southern California as a dying tropical storm. Consequently, much of southern California was placed under the first tropical storm warning in history. But these strong steering winds also sheered the storm apart and tore it to pieces as it approached. The powerful updrafts, towering clouds, and tropical moisture were quickly swept to the north far ahead of the core of circulation, as it skimmed by the central Baja coast. Though moisture from the cyclone spread into Baja and southern California more than a day ahead, the eye of the deep low pressure and circulation into it became difficult to detect as it grew less organized and was torn to shreds.

Follow these NOAA images from August 19:

From the ground, a few odd weather observations would only suggest that a tropical cyclone might be approaching the Southland. Scattered thunderstorms had built up over our mountains and deserts during afternoons before Hilary arrived, but they were typical of the summer monsoon moisture that sometimes slops into southeastern California from the Sonoran Desert. The only hints that a big storm might be coming were the progressively thicker high and middle-level clouds streaming off of Hilary and over our region. Though unusual, Saturday’s gradually increasing cloud cover was not unheard of for August. After all, these could have been debris clouds drifting off the previous day’s monsoon thunderstorms over the Sonoran Desert. But, as dew points increased into the low 70s and precipitable water (the amount of water that could be drained from one entire column of air) increased toward 2 inches, we were entering uncharted summer weather territory. We can thank NWS forecasters, using their forecasting technologies, for encouraging local officials to prepare our infrastructures to manage California’s first tropical storm in more than 80 years.  

Hilary raced north to make landfall on the Baja coast just south of the border on Sunday, August 20. This, along with regional wind conditions previously mentioned, helped to save the Southern California Bight from the high waves and storm surge we associate with big hurricanes that strike Florida and U.S. Gulf states. Our beaches and coastal flatlands were spared such destructive drama. While officials in coastal communities had played it safe rather than sorry, some were wondering if this big tropical storm talk was just big hype. By the time Hilary got to southern California, it was difficult to identify any organized eye or other center of circulation. But this had become two different storms. One showed up as a day of steady rains and mostly gentle swirls of winds around the coastal plains. The other Hilary ravaged slopes farther inland over the mountains and into the deserts with torrential rain and high winds. As the moist air was forced up mountain slopes, copious amounts of orographic precipitation were drained out in the form of heavier cloudbursts. So the mountains and deserts experienced the brunt of this storm that moved inland.     

Follow these NOAA images from August 20 as Hilary swept into SoCal:

When Hilary swept across those massive mountain barriers that extend north from the Mexican Border, the storm became further disorganized. Sustained winds peaked at over 50 mph with gusts over 60 mph within the updrafts, downdrafts, and turbulent eddies that formed along mountain slopes. Rain totals over 6 inches were recorded from San Diego County mountains north into Canyon Country in L.A. County. Desert slopes adjacent to those mountain ranges (from near Borrego Springs to Palm Springs to Whitewater to Palmdale) received nearly as much rain, but on surfaces with little protective vegetation to absorb the water. Mud and debris flows with nowhere else to go buried roads and some neighborhoods (such as in Cathedral City), even blocking major Interstates I-8 and I-10. Within one day, Hilary’s unprecedented moisture plume continued streaming north across the Mojave and into the Basin and Range. Death Valley recorded its wettest day in history. And though officials anticipating the destruction had closed the park to visitors, about 400 people were stranded within park boundaries when roads were washed out or destroyed. Squeezed by winds streaming between those two massive pressure systems, the now disorganized moisture plume continued flowing north, delivering some precious water to drought-stricken regions northeast of Nevada. By Tuesday, August 22, Hilary was already history. Though several mountain and desert communities had plenty of digging out to do, Hilary’s quick hit impacts weren’t as catastrophic as a tropical cyclone that could have wobbled around and dissipated over us for a prolonged period.

The big rain winners were mostly at higher elevations along and near the spine of the Peninsular Ranges and up into the Transverse Ranges. The official gauge at 8,616 feet asl, near the top of the Palm Springs Tramway, recorded 11.74 inches from the storm, while surrounding regions that included Idyllwild topped 7 inches. The Baywood Flats gauge at 7,097 feet in the San Bernardino Mountains recorded 11.73 inches, while surrounding locations that included Lytle Creek also accumulated more than 7 inches. Mt. Wilson caught more than 8.5 inches. Some higher terrain in San Diego County (including Mt. Laguna) also got more than 7 inches of rain from Hilary. As mentioned, L.A. County’s Canyon Country topped out at about 7 inches. Surrounding vulnerable desert terrain and recent burn scars delivered the most damaging mud and debris flows. The next day, as Hilary’s remnant moisture sprinted farther north, the National Weather Service Las Vegas Office issued this message after debris flows sprawled across the desert floor:
“Yesterday (August 20, 2023), Death Valley National Park observed 2.20″ of precipitation at the official gauge near Furnace Creek. This breaks the previous all-time wettest day record of 1.70″, which was set on August 5, 2022.”    

Follow these images from August 21, as what remains of Hilary slop far to our north:

You might say the rain losers were in the coastal flatlands of San Diego and Orange Counties (many locations didn’t make it to 2 inches), where Hilary’s moisture lacked the final lift required to ring out her tropical air masses as she simultaneously collapsed and sprinted by. Nevertheless, numerous weather stations in southern California’s coastal plains received record August rainfall in just one 24-hour period. (See the record totals in our image from the L.A. National Weather Service Office.) More than 3.5 inches of rain in one 24-hour period would make history at any time of year here in Santa Monica. But such rainfall totals in August were unheard of. Until now. 

That was a quick summary of the life and times of tropical cyclone Hilary as her dying remnants staggered or rampaged through a well-prepared southern California. The good news is how this storm soaked our higher-elevation forests and lower-elevation Mediterranean plant communities that are normally dehydrating into the most dangerous fire seasons of the year. Quick deluges bumped up moisture content in our soils and vegetation and rejuvenated springs and streams that normally dry up this time of year. We can see formerly drooping and wilting plants in our gardens and on our slopes that are suddenly and surprisingly reawakened, while other species seem to not know how to respond to so much water in the middle of summer’s Mediterranean drought. Even parts of the Mojave Desert that were shielded from winter’s drought-busting atmospheric rivers were finally lifted out of official drought categories by this storm. But contrary to a few media stories, Hilary didn’t add significant new supplies to California’s water capture and distribution projects, since most of them are in northern California drainage basins not impacted by Hilary. In SoCal, a small portion of the runoff was pooled in spreading basins to percolate and recharge groundwater supplies, but much of the flash flooding was not captured.

If you’re still interested in viewing the more dramatic videos showing flood damage and destruction from Hilary, you can click one of the links that follow this story.

It’s been a bizarre 2023 weather year. We are plunging into an El Nino event in the Pacific, which is forecast to continue into winter. On to the next weird and wild weather anomaly… and our new weather and climate publication scheduled to appear early next year.             

The post Hilary Makes Weather History in Southern California first appeared on Rediscovering the Golden State.

Classic extreme orographic precipitation and rain shadow effects were on full display across California during the wet winter of 2023. Coastal and mountain locations experienced a wetter-than-normal rainy season, some with double their average rain and snow totals. But precipitation dropped off dramatically as the air masses drifted southeast and down into the deserts. San Diego County offers excellent examples. The slopes around Palomar Mountain received more than 50 inches of water-equivalent precipitation. The official NWS station at Anza Borrego, located on the eastern rain shadow slopes of the same Peninsular Ranges, recorded less than 10 inches of rainfall, which is also a wet year for them. Just about 25 miles farther east, down around the Salton Trough of Imperial County, seasonal rainfall totals were only near an inch. The storms could be seen drenching mountain slopes to the west, but they dissipated when air masses descended into southeastern California’s lower deserts. Similar extremes were recorded as the inundated San Gabriel and San Bernardino Mountains blocked heavier rains from soaking parts of the Mojave Desert.     

The results were colorful superbloom desert landscapes up along Peninsular Range and other mountain barriers and slopes, but with abrupt transitions to desolate arid terrain to the east, where you had to look more carefully to find flowering plants. Follow us as we venture around Anza-Borrego Desert State Park in April. We will discover colorful landscapes with numerous species celebrating the seasonal rains, while less fortunate desert locales to the east continued to struggle through debilitating drought. Click on to Page 2 to view high desert blooms around the Antelope Valley Poppy Reserve. In both cases, we will observe some flowers and colors that only appear after exceptionally wet years.

Now you can click on to Page 2 to explore the memorable April superbloom farther to the north, in our high desert.

The post Chasing the Desert Superbloom, 2023 first appeared on Rediscovering the Golden State.

So what does it take to produce a superbloom?

Several factors must align, and in the right order, for a superbloom to occur. The first and most important is rainfall. California’s wildflowers require significant amounts of rain to germinate and grow. And this year we have had plenty.  Specifically, they need a steady rain in the fall and winter months, followed by consistent warm temperatures and sunny days in the spring.

It is that last part of the equation that is the trickiest. If it warms up too quick the delicate flowers can dry out too fast. If the nights are too cold frost can either damage the plants or delay their flowering.  

With these factors in mind, it’s no surprise that the Carrizo Plain National Monument is one of the best places in California to witness a superbloom. Located in the southwestern part of the state a bit southwest of Bakersfield, the Carrizo Plain is a vast expanse of grassland and rolling hills that is home to a variety of wildflowers.

In the past couple of decades, the Carrizo Plain has experienced several superblooms, drawing swarms of visitors from across the state and beyond.  The last bona fide superbloom was in 2019. In most years this explosion of color occurs in early to mid April. Some of the most common wildflowers that can be seen during a superbloom include:

California Poppy (Eschscholzia californica): The California poppy is the state flower of California, and it’s easy to see why. The flower’s vibrant orange color is a sight to behold, and it can grow up to 12 inches in height. The petals of the flower are delicate and may appear slightly crinkled, giving it a unique texture.

Lupine (Lupinus sp.): Lupine is a genus of flowering plants that includes several different species. In the Carrizo Plain, you may see several different types of lupine, including the Arroyo Lupine (Lupinus succulentus) and the Miniature Lupine (Lupinus bicolor). Lupine flowers can be blue, purple, pink, or white, and they typically grow on tall stalks that can reach up to three feet in height.

Goldfields (Lasthenia sp.): The goldfields is another genus of flowering plants that is known to bloom in the Carrizo Plain. The flowers are small and daisy-like, with yellow petals and a dark center. They can grow in large clusters, creating a sea of yellow that is truly stunning.

Blue Dicks (Dichelostemma capitatum): Blue dicks is a perennial plant that is native to California. It produces showy clusters of star-shaped flowers that can range in color from pale lavender to deep blue-purple. The plants are typically less than two feet in height, with narrow, grass-like leaves.

Owl’s Clover (Castilleja exserta): Owl’s clover is a unique flowering plant that is known for its distinctive shape. The flowers are hooded and tubular, with a bright pink or purple color. The plants can grow up to two feet in height, and they are often found growing in dense clusters.

Fiddleneck (Amsinckia sp.): Fiddleneck is a genus of plants that includes several different species. The flowers are small and tubular, with a yellow or orange color. They typically grow on tall stalks that can reach up to three feet in height.

But the Carrizo Plain isn’t the only area in California that offers an impressive display of wildflowers in the spring. Other notable locations include Antelope Valley, Anza-Borrego Desert State Park, and Point Reyes National Seashore.

In 2019, one California location experienced an exceptionally rare super bloom –which is when an unusually large number of wildflowers bloom at the same time. This event drew a massive number of tourists and flower enthusiasts to Walker Canyon near Lake Elsinore, CA, causing what only could be described as a circus-like atmosphere.

The crowds were so large that authorities had to shut down access to the canyon on several occasions, causing major traffic jams on the nearby freeways. People were parking their cars illegally along the roads, trampling over the wildflowers, and even causing damage to the environment that may take years or decades to fully repair.

In addition to the crowds, there were also vendors selling food, souvenirs, and other items, which added to the carnival-like atmosphere. Some visitors were even spotted posing for photos in the middle of the flowers, which contributed to the destruction of the delicate ecosystem.

Overall, the sheer number of people and the chaos that ensued caused concern among conservationists and local officials who were worried about the long-term impact on the environment.

As of this writing, the City of Lake Elsinore, Riverside County Parks, and the Western Riverside County Regional Conservation Authority (RCA) have listed Walker Canyon as closed to the public.

If you do venture out to the Carrizo Plain please know that the monument has many unimproved roads that can quickly become impassible in wet weather.  This is a remote area with no services and spotty cell-phone reception at best. A breakdown in the more remote portions of the monument could mean a long wait for help. Bring water and supplies.

Also, be sure to tread lightly and respect the delicate ecosystem that makes this fantastic, yet temporary, beauty possible. Stay on the roads, do not park on the flower beds and take only pictures while leaving only footprints.

Remember, these wildflowers are not just a pretty sight, but an important part of the Golden State’s natural heritage.

The post What does it take to produce a fantastic Superbloom? first appeared on Rediscovering the Golden State.

Unprecedented Patterns
California’s bizarre-turned-unprecedented previous (2021-22) rainy season may have been a clue to expect another round of the unexpected for the summer. We had experienced one of the wettest “winter” storms to ever soak our October. December brought a dramatic repeat performance with a storm that dumped record snowfall in the Sierra Nevada. Our winter season was off to a rousing start. But it suddenly stopped. Our traditionally wettest months (January and February) were perfectly dry in many parts of the Golden State in 2022, especially where we depend on accumulated snow packs for our water supply. As winter and spring progressed, it became clear that California was in big water trouble again. The stage was set for another year of weather patterns that would make seasonal weather averages seem meaningless.

Pressure on the Golden State
Many Californians, particularly in our inland regions, may remember the summer of 2022 as another series of searing and sometimes record-breaking heat waves. The culprit was an enormous oscillating high pressure system that wobbled over the western states, compressing and further heating summer air masses. But that wasn’t true everywhere. Along the immediate central and north coast, a rather shallow but dominant marine layer often spread familiar cool and misty fog and low stratus through July. The coastal strip was frequently stranded beyond the far western edge of that big high pressure dome. Meanwhile, an odd series of stubborn cut-off low pressure systems often stalled off the north coast, spinning just close enough to occasionally enhance the marine layer, but offering little or no relief farther inland.

On the Edge of the Southwest Monsoon
Another form of heat relief arrived in our deserts. Clockwise circulation around that same southwestern high pressure (often labelled as summer’s familiar Four Corners High) carried moist, subtropical air masses up from the southeast. This fueled another intense, soaking monsoon season in the desert southwest that started in late June and continued on and off into October. As thunderstorms rumbled across northern Mexico and Arizona, their showers and/or debris clouds often slopped into southeastern California. The moisture and cloud cover, though adding sticky humidity, provided some temporary relief from otherwise oppressive desert heat. And when the Four Corners high pressure wobbled into more favorable positions, clouds and storms briefly flooded north along the spine of the Sierra Nevada Mountains and into the Basin and Range, and more briefly invaded other parts of the state where they are rarely observed during summer.

All-time Heat Records Fall
September brought historic changes. The massive high pressure system that had dominated the west expanded over California during the first week of the month. Tall, dense, heavy stacks of air descended on the state, as if a pressure cooker was compressing the air masses toward the surface. Weather stations from Reno to the Bay Area to the Oregon border broke September high temperature records. Redding made it to 115°F. September 6 was the big winner. Parts of the Central Valley measured the hottest temperatures EVER recorded, including Stockton (115°F) and Sacramento (116°F). All-time records were also set across and around the Bay Area: Santa Rosa (115); Napa (114); Livermore (116); Redwood City (110); and San Jose (109). The heat spread into places such as the Salinas Valley, where King City sizzled to a record 116°F. (Thanks to the National Weather Service for these official readings.)

Unseasonable Rains Chase the High Heat
Just more than a week later, yet another very different record-breaking weather pattern formed; but this loomed off the coast. Another closed low pressure system, spinning off the north coast, intensified until it began resembling one of winter’s North Pacific middle latitude cyclones. As it approached, it tossed moisture and instability into northern and central California. Scattered thunderstorms, heavy downpours, and local flooding swept inland. The heaviest rains circulated through on September 18 and 19. Storm winners included a large area around Davis, which received nearly 4 inches of rain in less than two days. Local power outages and flooding prompted officials to respond to freak weather patterns they had never observed in September, in places that average about 1/10^th of an inch of rain for the entire month. A bizarre September capped another odd summer; flash flood watches and warnings spread especially into areas that had been burned into vulnerable landscapes during scorching heat waves and damaging wind storms of previous years.

Exploring Disparate Weather Patterns, Climates, and Landscapes
We can see how observing and noting each year’s weather patterns has increasingly resembled science fiction movie scripts. But we don’t have to ignore the effects of climate change to appreciate and marvel over some of the sky décor painted by these weather patterns. So, the remainder of this story is a sky appreciation photo essay. Our text here lays the foundation and sets the stage so that we may explore the “why” of spectacular and sometimes breathtaking weather as it was displayed for our enjoyment. This first page also displays a few weather maps and satellite images during some of our unusual summer weather patterns. The second page takes you to the unstable skies of the eastern Sierra Nevada and Basin and Range to explore summer’s turbulent clouds and storms. The third page transports you just 200 miles west to the central coast, where we observe summer’s moist, stable marine layer fog and relatively routine, innocuous low stratus. Only two hundred miles separate these two Californias that seem worlds apart just about every year, including this one month in the summer of 2022. After viewing the exceptional maps and satellite images on this page, click to the next pages to follow us on this latest amalgamate of art and science. Our efforts will eventually lead us toward a much larger project and publication on California’s weather and climate. Stay tuned. 

August Skyscapes: Click on to Page 2 to view unstable summer clouds and storms above the eastern Sierra Nevada and Basin and Range. Click on to Page 3 to view the relative calm and stable marine layer along the central coast (only 200 miles from our Page 2 images) during the same summer of 2022.

The post Finding STEAM in our Summer Skies first appeared on Rediscovering the Golden State.

That leaves you a lot of latitude for exploring what interests you, pun intended! Heck, the ideas generated by this revelation could start sprouting like mushrooms after our recent rains. Which reminds me …

Today we are highlighting the work of Christopher Campbell, a student in the GIS program at Santa Monica College. In the link below, Christopher delves into the where and the why in California of the elusive wild morel mushroom. The story that unfolds in his text, maps, and photos is as interesting as it is informative. He shows us that we can systematically explore and understand any natural wonder of interest to us, provided we employ sound scientific reasoning as well as basic geographic concepts and principles.

Morels by Christopher Campbell

So, the moral of this story is that whatever you find fascinating — in the Golden State or elsewhere — the science of geography and the tools of GIS can be your guides to securing a deeper understanding of that which sparked your curiosity.

If you are interested in learning GIS at Santa Monica College, please check out their offerings in Geography Program in the Earth Sciences Department.

** Rediscovering the Golden State: California Geography welcomes submissions of California-themed projects from students and faculty from any CA institution of higher education to be highlighted on our web site. This includes, but is not limited to, articles, papers, maps and presentations– GIS or otherwise).

Even if you are working/ studying outside CA, we’ll consider your contributions too, provided the content has a clear and unambiguous connection to California geography.

For more information: info@rediscoveringthegoldenstate.com

The post The “Morel” of the Story … first appeared on Rediscovering the Golden State.

(Where you see numbers blocked in parentheses, you might consult Page 2 of this story for more detailed definitions and explanations.)

Following the Monsoon
The summer monsoon arrives in the Southwest with towering cumulus and cumulonimbus clouds and sudden thunderstorm downpours that can deliver more rain in an hour than what may have accumulated in the previous several months. The storms become especially common during afternoon surface heating in the high country of New Mexico and Arizona, as moisture drifts up from Mexico. Many of these locations experience peak annual precipitation from July into September. (As a related update, check out this NWS story about how monsoon thunderstorms became severe and deadly in Phoenix, AZ on July 24, 2024.) Occasionally, when upper level pressure and wind patterns are favorable, this moisture and instability will drift across the California border, into southern California deserts and mountain ranges, and even up the spine of the Sierra Nevada Mountains. This usually occurs when a strong upper level high pressure system wobbles somewhere near the Four Corners Region, pushing winds clockwise around it, creating wind flow out of the southeast over us, and advecting moist air into southern parts of our state. Though only a few California locations near the Colorado River receive their peak annual precipitation during late summer (and it’s usually not much), these brief monsoonal encroachments can bring isolated summer storms more common to Flagstaff or Taos into parts of southern California and beyond.

Exceptional Storms in the Summer of 2021
During July and August of 2021, an unusually early and then wet monsoon season soaked and then flooded parts of New Mexico and Arizona with heavy rain and deadly flash flooding that even broke some records. In a few cases, the disturbances, instability, and moisture drifted into California with some spectacular results. Deserts and mountain ranges from the Colorado River to southern California’s mountain ranges, and from the Basin and Range to the Sierra Nevada had been dehydrated by months of relentless drought and record high temperatures. Suddenly, relief appeared in the form of subtropical clouds that shielded the blazing sun and then towering thunderheads carrying torrential downpours and spectacular lightning displays. Lightning strikes within drier thunderstorms with higher cloud bases increased fire dangers, while wetter storms delivered life-giving cloudbursts that quickly soaked soils and even generated some flash flooding. Though these storms were characteristically widely scattered and of short duration, this reoccurring pattern during July and into August eventually dumped surprising amounts of measurable rainfall on nearly every weather station, including places such as Death Valley.

Monitoring and Chasing Summer Moisture
I was fortunate to anticipate and then chase some of these legendary-but-misunderstood storms during one day on July 30, 2021. For several days, wind flowing from the southeast had been sporadically delivering moisture from Arizona and Mexico into the state. Record wet air masses with high dew points were flooding Arizona, even driving afternoon high temperatures down into the low 80s (~28 C)in Phoenix for three straight days, another record for July. And some of this moist air was moving across the Colorado River Valley and the Mexican Border into California.

Mountains Accentuate Air Mass Ascension
My search for thunderstorms started in San Gorgonio (Banning) Pass, where a thunderhead had already built over the San Bernardino Mountains by noon, delivering narrow rain columns to quench local slopes. Another impressive cumulonimbus towered higher on the south side of the pass, wavering over and near San Jacinto Peak. (2) Air flow from the southeast sheared its top over the pass. Heavy shafts of rain poured on to the northern slopes of the San Jacintos and into desert canyons, above where Hwy 111 toward Palm Springs forks off of Interstate 10. (3) I suspected that this already impressive build up could produce some surprising rainfall totals around the San Jacinto Mountains, but I wanted to monitor the development of a desert storm. (Sure enough, these mountain storms would eventually build further into the afternoon until more than 1.6 inches (~4 cm) of rain fell in Idyllwild in a violent cloudburst that lasted less than two hours.) My desert storm drama would come later in the day.

Science-savvy Gambling with Cumulus
Monitoring updated radar and satellite imagery and some specifics in the forecast, I noticed the monsoon moisture still streaming in from Mexico and Arizona and so I headed east along Interstate 10 past Indio. As thunderheads continued to build over the now-distant San Jacinto and Santa Rosa Mountains, I continued east up the I 10 hill toward Chiriaco Summit.  A few NWS flash flood warnings for nearby regions interrupted radio and phone reception. But as I turned off toward Joshua Tree National Park, the desert remained relatively hot and quiet with only a few small puffy cumulus clouds below a thin veil of higher clouds, all combining to decorate the sky. Following this road north, I noticed a line of small, but well-defined cumulus popping up in the afternoon thermals over the park’s peaks. And so, I decided to make my stand around here. Most casual observers might have considered these little clouds to be innocuous scene enhancers. But they were forming along a line as moist air now heated by direct afternoon sunlight was buoyed up along Joshua Tree Park’s western slopes, which rise above the Coachella Valley. After about an hour that included a short self-guided nature trail through this sizzling desert of dead and dying plants, a landscape clearly suffering from exceptional drought, my gamble paid off.

Tranquil Desert Turns to Violent Waterworld
As suspected, the cumulus I targeted suddenly began to blossom into towering icy cauliflowers. Within another half hour, a dense rain shaft had formed and the impressive storm was producing constant rumbling thunder. Its downdrafts soon obscured desert peaks and slopes that included Monument Mountain to the northwest of the Cottonwood Springs Visitor Center, which was closed for the summer. I meandered up Pinkham Canyon dirt road toward the storm, but finally turned around, knowing what could happen should a downpour suddenly spread over me. Returning back on the main road through the park, I pushed north along Pinto Basin Road for a few miles to where it intersects Smoke Tree Wash. By then, the storm had dramatically strengthened and expanded, producing frequent lightning and violent downbursts of rain and hail from west to east across the sky and the road. A process called back-building seemed to keep the storms spreading across the park, into the prevailing winds. Roaring waterfalls from the sky were pouring over me and the surrounding exposed terrain. I stayed long enough to experience the excitement until it was raining so hard and so long that I knew it meant danger. So, I turned back around to higher ground, away from this wash with smoke trees, just before the flooding could make the road impassible. (Smoke Trees (Psorothamnus spinosus) grow in linear patterns along usually dry desert washes for a reason. Their seeds are abraded by flash floods and debris flows that encourage germination; later, the wash provides access to a little more ground water than surrounding desert terrain.)

Turn Around, Don’t Drown
By then, violent downdrafts were delivering ominous sheets of rain in buckets from storms to the west and east that then merged overhead. As winds gusted up to 40 miles per hour, funnel cloud formations could be seen rising up into the cumulonimbus after nearly touching the desert floor. It turned almost as dark as night on this July 30 afternoon. It would have been nice to try to document the few hours of potentially deadly flooding that damaged and closed roads within the park. But, I was wise to follow the “turn around, don’t drown” rule that echoes across the Southwest during this time of year. So, I headed back uphill toward the Cottonwood Visitor Center, out from under the frequent lightning strikes and curtains of roaring torrential rain that had created this temporary chaotic waterworld in the California desert. Violent storms continued migrating across the park, sending destabilizing outflows ahead and feeding off the remaining heat rising from surfaces not yet cooled by cloudbursts. Within a couple of hours, the sun was setting, while other destabilizing heat sources were pinched out by the cooling rains. (4) A few nature photographers, attracted by the electrical displays, attempted to capture some lightning photos just before dark as the storm quickly dispersed and more quickly dissipated, mostly retreating toward the east.

Appreciating Summer Cycles
Those who traveled across the desert that afternoon and evening were treated to what many Californians might consider an oddity. But, for most folks familiar with the desert southwest, such as vehicle passengers displaying Arizona and New Mexico and Utah license plates, it was just another example of how the summer monsoon can put on a dazzling sky show. And it is likely that the plants and animals caught under those cloudbursts, previously dehydrated and desiccated by unprecedented drought, were lucky to survive until this brief soaking that would get them through one more summer.

Unreliable but Spectacular
Most Californians are accustomed to the hours and days of more widespread, steady rains brought by winter’s migrating middle latitude wave cyclones off the North Pacific. And it is true that nearly all of the state’s precipitation is delivered from such systems that migrate farther north during the warm season, leaving us with months of summer drought. These patterns help define our Mediterranean climate.  It is also true that our surprise and sporadic summer showers can’t compare to regions with direct sources of tropical air (such as around Florida) where wet thunderstorms might march across the heated land during each summer afternoon. In the Southwest, summer weather conditions and surface and upper level wind patterns must conspire to draw in moisture from more distant sources. But such infrequency doesn’t minimize the drama and excitement and the relief from summer’s dry heat that these pop-up summer thunderstorms can bring, especially along the Colorado River Valley, across inland California, and up the ridges of the Sierra Nevada Mountains.

Forecasting One-tenth to Five Inches of Partly Cloudy
National Weather Service forecasters are challenged by extreme variabilities and inconsistencies in local summer monsoon storm and rainfall patterns, especially when the public doesn’t understand these events. On the coastal sides of the mountains during winter and pretty much all year in the coastal basins, a 20% chance of rain means it will probably not rain, and if it does, it will be some kind of drizzle. During the southwest monsoon in inland California, there could still be an 80% chance that it won’t rain at any one location; but local folks should know that wherever isolated monsoon storms develop, they could produce memorable gullywashers and even brief serious or deadly flooding. This uncertainty doesn’t connect with most clueless visitors from coastal cities. Usually, forecasters write the estimated, generalized precipitation totals and follow it with a phrase such as “however, greater amounts may occur during storms.” As mountain weather watcher Steve Chadwick notes, it might be clearer to write, “Isolated heavy rains and flash flooding are possible throughout the forecast area”, to warn those who are less experienced. Or, they could use Steve’s more humorous interpretation of these weather events: “one-tenth to five inches of partly cloudy.”

If you are interested in more details about weather conditions during the observed storms on July 30, 2021 in Joshua Tree NP, go to Number 5 on our scientific definitions and explanations Page 2. (5) 

The post Storm Chasing in the California Desert first appeared on Rediscovering the Golden State.