Monday, April 17, 2017

Work as a Biology Instructor at Modesto Junior College!

It's true it's not geology, but this is really a natural history blog, and I want to make you aware that Modesto Junior College is currently seeking an instructor of biology (tenure-track). If you are seeking employment as a biologist, Modesto Junior College is a marvelous place to teach. Our Science Community Center is a very well-equipped facility, and the staff here is a great bunch of people to work with. The Great Valley Museum fills the ground floor and will soon start construction of the Outdoor Education Center. The region is an excellent base camp for excursions to the coast (Big Sur and Marin Headlands), the Sacramento Delta, the wildlife refuges of the Great Valley, and the Sierra Nevada. It's hard to imagine so many habitats in such a small area.

If you are interested and qualified, check out the job announcement at

Saturday, April 15, 2017

Pygmy Mammoths? An Oxymoron Maybe, But Here's the Story, and a Great Opportunity for Exploration of the Channel Islands

For me, one of the most intriguing stories of California geology was the adventure of the mammoths of the Channel Islands. The islands lie offshore of Ventura and Santa Barbara in southern California, and are mostly protected as Channel Islands National Park. The largest island, Santa Cruz, is mostly maintained by the Nature Conservancy.

Several species of mammoths ranged across America during the ice ages and the intervening warm periods, and as their name suggests, they grew to immense size (the Columbian Mammoth was 11 feet high at the shoulder). At some point some tens of thousands of years ago, some Columbian Mammoths swam to the islands. This idea sounds mildly ridiculous, but it turns out that elephants in general are excellent swimmers with a natural snorkel, and can easily swim for many miles. And, with the drop of sea level during the ice ages, the islands were larger and the shorelines closer to the mainland (most of the islands were once a single landmass called Santa Rosae).

The mammoths found a large island with rich food sources, and a lack of predators. They thrived, but then conditions changed. The ice ages ended and sea level rose, shrinking the large island into four smaller islands. Food sources were limited and life became more difficult for the mammoths, especially the largest ones who needed far more food. In a twist on the usual story, it was the runts of the litter who thrived, because they could live with less. They had better survivability, and that began to show in their genetic code. The adults of new generations were smaller than their ancestors, and eventually there were fully grown mammoths that stood only 5 feet high and were only a tenth the weight of their mainland cousins. On some islands of the Pacific Rim, dwarf mammoths survived until just 3,650 years ago, but unfortunately humans arrived on the Channel Islands and may have hunted them to extinction 10,000-12,000 years ago.

This is just one of many fascinating stories of the Channel Islands, stories of geology, biology, and anthropology. I'm writing this blog to bring attention to an innovative class being offered by my institution, Modesto Junior College, Anthropological and Biological Field Studies of the Channel Islands (Anthro 155 and Biol 155, a total of two units). It is being taught by two of my colleagues, Teri Curtis (Biology) and Susan Kerr (Anthropology). The trip includes several pre-trip meetings, and a field trip to Santa Cruz Island from May 30 to June 4th. The cost (not including tuition) will be $510, which includes lodging (one night camping), transportation (including vans and an island ferry), and food. It will be a fascinating experience!

If you'd liked to learn more about this wonderful opportunity, there will be informational meetings on the following days:

4/25/17: 5-6pm, Center for Advanced Technologies (CAT) Room 201 MJC east campus.
5/5/17: 6-7pm, Great Valley Musuem Discovery Room MJC west campus

For more information, contact Teri Curtis at curtist(at), or Susan Kerr at kerrs(at)

General information about the Channel islands:

Wednesday, April 12, 2017

The Way it Was Today: There's Nowhere on Earth Like the Ahwahnee

Yes it is true that I am privileged. I live just ninety beautiful miles from this place, Yosemite Valley in the middle of Yosemite National Park in the Sierra Nevada of California. Everyone should be this lucky. It is a treasure beyond the dreams of avarice because its value doesn't lie in money. The value of this place is spiritual. The government of the United States dimly realizes this, and that is why it became our first national park in technical terms, although officially it was the third. Abraham Lincoln ceded the valley to the state of California in 1864 to be preserved forever. Yellowstone became the first actual national park in 1872, and Yosemite became a park in 1890, just a few weeks after Sequoia National Park a few miles to the south.
The valley's true name (in the sense that those who discover it get to name it) is Ahwahnee, the name given by the ancestors of the original inhabitants, the Ahwahneechee. They had been living in and near the valley for at least 3,000 years, and possibly many more. The name Yosemite was given by the European colonizers who arrived only a century and a half ago. It was a corruption of the Native American name for "Grizzly Bear" or "Killer".
Yosemite Valley is often described as a monument to glacial erosion, but it is so much more. In a very real sense, exploring Yosemite is the equivalent of seeing Yellowstone, Mt. Rainier, or Crater Lake from 5 or 6 miles below. We gaze on the granitic rocks and realize they are the magma chambers for volcanoes and calderas that once existed miles above. The volcanism ceased, the land was uplifted, and deeply eroded. Rivers caused deep gorges to form, and in the final moments of geological time glaciers scoured the canyons, reshaping them into the towering cliffs and waterfalls that we see today.
We were there on a geology field studies trip on Sunday, the day after a fairly intense storm. It was beautiful beyond measure. There were members in the class who had never seen the place before despite living close by, and they were in awe. I estimate that I've visited the park close to 100 times in the last 28 years, but I was no less in awe than were my students. This is one of those places that is worth the effort to see before you pass on. It's a treasure beyond imagining.

If you've been reading my blog for any amount of time, you know I've written comprehensively about this place, and then some. I offer up my blog series, Under the Volcano, and Into the Abyss, a study of the geology of the valley and surrounding regions.

Monday, April 10, 2017

From the Archives: The Other California- A Wandering Volcano and a Floral Outburst

I don't expect to be able to visit the Southern California "Superbloom", this year, but I have seen it in the past, and thought you might enjoy some geological perspectives on why the poppies do so well in the western Mojave Desert. I found it an interesting story. I also updated the photos to include higher resolution  and added a few bonus shots. This story appeared April 18, 2010 (that's the late Pleistocene in blog years...)

I can still be astounded....

There are lots of things I haven't seen and done in my life, but I can imagine what it is going to be like to see a rhyolitic volcano erupting at close quarters, or to feel a magnitude 8 quake (6.9 is my biggest so far). But sometimes things happen that just leave me breathless, if only from the unexpectedness of it all. That's what happened to me today.

I had always heard about the Antelope Valley California Poppy State Reserve, but had never seen it, especially in the late winter or early spring when the blooms are at their peak. We were taking an alternate route home, generally following the San Andreas fault from Cajon Pass to Grapevine Summit on Interstate 5. The desert was mostly dry and barren for much of the route, but as we passed Palmdale and Lancaster, I looked west and saw something I had never seen before: orange hills. Fluorescent orange hills. As we drew closer, it was clear that the California Poppies were at their golden best.

After expending several hours using vast amounts of digital space on my camera, I started to ponder why the flowers were here, and not elsewhere across the Mojave Desert, at least not in such dominating numbers. I first considered the slightly higher elevation, the local rocks and sediment, soil conditions and drainage, but I started to realize there was another dynamic going on...the flowers are a natural phenomena, but a natural phenomena with a very human influence. About seven miles west of the Poppy preserve there is another state park: Arthur B. Ripley Desert Woodland State Park. The park preserves 580 acres of what turns out to be the native land cover of the Mojave Desert west of Lancaster and Palmdale: juniper woodland and Joshua Trees.

A century ago, this high end of the desert was cleared of Joshua Trees and Juniper, usually by chaining (dragging a huge chain between tractors that knocked down whole forests) or fires in order to put in thousands of acres of alfalfa fields and other crops. Large areas were reserved for sheep and cattle grazing as well. The natural plant cover was long gone. Much later, some of the abandoned fields started to recover, and the showy wildflowers represent some of the pioneer species (I've noticed for years that the best wildflower shows in any forested areas occur after fires: Yellowstone, Yosemite, and many other areas). Without any nearby natural vegetation, there is no way for the native Joshua Trees and other large trees and shrubs to recolonize the valley floor; they don't have any method to spread their seeds widely (Joshua Trees were once spread in giant ground sloth poop...). Despite their incredible beauty, the wildflower displays are a monument to our extensive alteration of the environment that once existed here.

Just the same, the flowers were one of the most intense displays of color I've ever seen. Lest you think that I had discovered some isolated and unknown Eden, well, a look at the photo below should dissuade you from thinking that these poppies are a well-kept secret. It was actually impossible to get to the park visitor center due to the traffic. Just the same, there was plenty of parking both east and west of the park, and the poppies and other flowers were every bit as abundant. We had no trouble finding some wonderfully quiet corners to contemplate the beauty (addendum: trampling of the flower meadows is a real concern, especially this year. If you visit, stay on the roads and trails).

As to the wandering volcano of the title? Just west of the preserve, some unusual rock outcrops can be seen near the junction of Lancaster road and Highway 138 at Neenach. These rocks, the Neenach Volcanics, are about 23.5 million years old, and lie adjacent to the San Andreas fault. The volcano is only half here; the remainder sits on the other side of the fault, 195 miles to the northwest, at Pinnacles National Monument, which I have discussed earlier, here and here. For several reasons, the Neenach Volcanics have not been exposed in the spectacular manner of the rocks at Pinnacles, but the story they tell is just as compelling.

So there, I found a geologic connection that allowed me to show you some flower pictures. You'll probably see a few more gratuitous flower pictures in coming posts. I took around a hundred, and I have to show them to somebody...

For those who are new to Geotripper, the "Other California" is my long-running web series on the fascinating geological places in my fine state that don't usually show up on the postcards (although I've been known to break my own rules every so often; California's poppies are on postcards all the time).

Thursday, April 6, 2017

Liveblogging the Deluge, April Edition: Seeing Half Dome Reminded Me of Something

It's easy to get distracted by life at times. After four months of well-above average rainfall and snowfall caused by a series of atmospheric river storms, we here in California were left in a rather precarious situation where our reservoirs were too full and experiencing damage, and where our rivers were swollen with snowmelt, straining the levees and threatening to flood valley towns. Then the storms stopped for awhile. Locally, we only had one series of storms worth noting in March, and only 1.85 inches of rain fell. That's above average for the month, but it's also the lowest monthly total since November. We climbed past the 20 inch mark for only the fifth time in the 28 years that I've been measuring rain in the backyard. If not another drop fell, this would be the fourth wettest year that I've measured since 1990 (another inch is expected this weekend). But we've now had a few weeks of dry conditions, and it can be easy to forget that there is still a situation...up there.
I was reminded of this as I drove south to teach a class this evening. I noticed it was unusually clear, and I realized it was a good day to photograph Half Dome from Oakdale Waterford Highway on the floor of the Great Valley. It's one of the better vantage points for spying the iconic dome, and it was nicely framed by the snow-covered high country. There is still a massive amount of snow up there, and I realized it was time to get an update on the deluge that California has been experiencing this year after half a decade of crippling drought.
Here's how things stand. The brief respite from the constant storms has allowed the dam operators to release some of their excess water, preparing for the coming snowmelt runoff. We've been lucky so far, avoiding any extended heat waves that could have caused serious problems. They've got some breathing space in reservoirs. And they'll need that space...
...because there is still a LOT of snow left in the high country of the Sierra Nevada. The April 1st snow report shows that the mountains are at 159% of normal for this time of year. The Tuolumne River drainage has enough snow to fill Don Pedro Reservoir once over. The operators know it, and the river downstream has not been allowed to drop below flood stage since January 4. It's running at 11,400 cubic feet per second, and will probably remain close to that level through the beginning of summer. I can barely imagine how the river channel will be changed when it emerges months from now.

We are not out of the woods yet. Floods are still a possibility, especially if we get hit by a heat wave. And we still have at least one more major storm coming this weekend. Stay dry out there!

Monday, April 3, 2017

Explore the Pacific Northwest and Northern Rocky Mountains with Geotripper! June 17-July 1, 2017

Grand Tetons National Park, Wyoming
Be forewarned. This post is a TRAP! It is designed to draw you in, weaken your defenses, and cause you to do something different than everyday life. Warning given...

Have you ever dreamed of hitting the open road and finally seeing those places you've dreamed about, but haven't acted on that dream yet? What if you found out about an excursion that doesn't just tour, but allows you to learn the geology and history of those wild places? A tour on which you can even earn college credit? AND, a tour that is affordable? Maybe this is the one...
Mt. Shasta, a Cascade volcano in northern California
From June 17-July 1, 2017, the geology department of Modesto Junior College will be conducting a field studies course (Geology 192) in the Pacific Northwest and Northern Rocky Mountains. It will be a three semester unit course designed for our community college clientele: first year geology majors, potential geology majors, and community members (especially teachers) interested in geology and natural history. We will develop the necessary geological background prior to and in the early days of the trip, so people of all backgrounds are encouraged to attend. The total cost is $800 which will include all food, camp fees, entrance fees, transportation costs for the trip. The tuition cost for the three units of semester credit will be around $180 (out of state tuition is higher, around $200 a unit, which is still a deal). The only additional costs should be for showers, laundry, books and other souvenirs, and junk food (we provide healthy food for the most part; if you want Twinkies you are on your own!). We will be camping each night, and the school provides the transportation (vans). The excellent meals are planned by our professional volunteer staff, and cooked by the participants under their watchful eyes.
Lava Tube in Lava Beds National Monument
What will you see and experience? On the 17th we'll leave MJC and drive north through the Great Valley of California and arrive at the south end of the Cascades Range. The huge edifice of Mt. Shasta looms over the north state at 14,163 feet, and still is potentially active. It last erupted in 1786. Depending on snow conditions, we'll climb to the 8,000 feet level at the old ski bowl and have a close look at the rock and ash deposits. We'll continue north and end the day at Lava Beds National Monument near the Oregon border. There will be chance to explore some lava tubes while we are there.
The view from Smith Rock State Park in Oregon
We drive through Oregon the next day, with possible stops at Crater Lake National Park and Newberry Crater (depending, once again, on snow conditions). Camp will be at Tumalo State Park. The following day we will explore Smith Rock State Park (above), Mt. Hood, and the Columbia River Gorge (if there is time we will climb Beacon Rock in the gorge). The third camp will be at Seaquest State Park at the foot of Mt. St. Helens in southern Washington.
Mt. St. Helens in Washington. It erupted in 1980 and 2004
The following day will be devoted to the exploration of Mt. St. Helens (weather allowing!). We'll then descend the eastern flank of the Cascades (including a close look at Mt. Rainier) and drive onto the Columbia River Plateau, a vast basalt plain that covers much of eastern Washington and Oregon. Camp will be at Wanapum State Park on the Columbia River near Vantage.
Dry Falls State Park in Washington. The floodwaters covered this entire landscape to a depth of 300 feet during the Spokane floods.
The next day we will view the evidence for vast floods that swept across the plateau during the Pleistocene ice ages. The discovery of these floods by J Harlan Bretz in the 1920s and the long road to acceptance of the hypothesis by the geological community is one of the great stories in the history of geology as a science. We'll have a look at the Channeled Scablands, Soap Lake, and Dry Falls as we travel east through Washington. We'll spend the night at Riverside State Park in Spokane, Washington.
Lake McDonald in Glacier National Park
We'll head through the copper mining districts of Idaho and into Montana where we'll see more evidence of the ice age floods, including the Camas Prairie where ripplemarks 30 feet high can be found. We'll end the day in a special place, Glacier National Park on the Montana-Canada border. We'll spend two days exploring the park, with chances at several hikes. The park is a showcase of glacial erosion, but the glaciers that exist in the park today are expected to be gone within a decade or two because of global warming.
Saint Mary Lake in Glacier National Park, Montana
When we leave Glacier, we'll head south through the high plains on the east side of the Rocky Mountains and end the day at the KOA in Bozeman, Montana. We'll check out the Museum of the Rockies, and depending on snow conditions, explore some of the high mountains that surround Yellowstone, and eventually drive the Beartooth Highway into Yellowstone, America's oldest national park. We'll spend two days exploring this incredible park.
Yellowstone Falls in the Grand Canyon of the Yellowstone River
There is the Grand Canyon of Yellowstone, and a menagerie of incredible animals, including elk, bison, moose, bighorn sheep, and if we get really lucky, wolves.
Wolf near Norris Geyser Basin, Yellowstone National Park
Then there are geothermal features for which Yellowstone is so famous. Grand Prismatic Spring, for instance, and 70% of the world's geysers (there's lots more besides just Old Faithful!).
Grand Prismatic Spring, Yellowstone National Park
We'll then head south and spend two days at Grand Tetons National Park with time for some spectacular hikes. Then we start the road home with a drive through northern Nevada to Berlin/Ichthyosaur State Park to see the fossilized remains of the behemoth swimming reptiles from the age of the dinosaurs. Finally, we expect to see Mono Lake and the high country of Yosemite National Park. If snow blocks our path, we head home over Sonora or Carson passes.
Big Geyser (not Old Faithful!) in Lower Basin, Yellowstone National Park

It's hard to describe the wonders that exist across the Pacific Northwest and Northern Rocky Mountains without getting an overwhelming urge to get up and leave right away. If you are interested in joining us this summer, please check out the course web page at and join our Facebook page at If you are in the Modesto region, we are having an information meeting on Monday, April 10 in the Science Community Center on the west campus of the Modesto Junior College at 7 PM in SCC 326 (attendance is not mandatory to go on the trip). We hope you will join us!

Saturday, April 1, 2017

Rock and Light: The Primal Elements of Death Valley, Monochrome Edition

Sorry for going all pseudo-Ansel Adams on you all. I was playing with the photo-editing program with the pictures that I used in yesterday's post, and at one point I switched to black and white. I'm enchanted by the colors of our planet, but it is easy to forget that features can often be better discerned in monochrome photos.
It's almost as if the blinding sun, so unexpected, blinded me to the textures and depth of the rocks revealed in the slopes of the northern Black Mountains of Death Valley National Park.  Monochrome imagery is something that really has only existed since the advent of photography, and its value today is in the unexpectedness of the image. We expect color, but it's not there. As Wikipedia (the ultimate authority) would put it, monochromatic images "are not direct renditions of their subjects, but are abstractions from reality". And yet, science illustrators often prefer to show objects of research in black and white, or even as drawings to emphasize the ultimate reality of their findings.
It occurs to me that monochrome images do have an impact on the human psyche, and it exists at a very fundamental level. Our vision at night is monochrome, and humans evolved with a certain primal fear of the darkness. One can't see approaching predators in the dark, and in low light one would be highly attuned to noticing small changes or movement in one's field of vision. Black and white images capture our attention in a way that color images just can't.
In any case, I was mainly looking for an excuse to put up some pictures that I found interesting. Badlands topography has always been a good subject for black and white photography because of the strong contrasts between light and shadow, and the Furnace Creek Formation is the ultimate expression of badlands.

Friday, March 31, 2017

Rock and Light, the Primal Elements of Death Valley

When one has been under gloomy overcast conditions punctuated by periods of rain for days, the novelty can run short, even in a place where rain is scarce. We had been on the road for three days and in that time we saw no sunshine, and in fact had lived through a night of record rainfall and localized flooding. What made the mood worse was that the weather forecasts had us expecting sunshine on the third day and we got rain instead.
The students were just great actually, showing all kinds of patience. They were in Death Valley after all, and they weren't in a classroom. At least not the kind with four walls. Just the same, I was pining for just a bit of sunlight, and the evening was coming quickly. We had just finished an exercise at Gower Gulch at the north end of the Black Mountains and we walking back to the vehicles when a sliver of sky opened up. The sun blazed forth in all its glory.
There are two sure things in places like Death Valley, rock and light. Deserts have dust storms at times, of course, but much of the time the air is free of pollution and humidity. The sun shines with an intensity not usually experienced in urban settings (my students traditionally come home with winter sunburns despite our warnings to use sunscreen).

And the rock...Death Valley has perhaps the greatest variety of rock types to be found in any national park. They range in age from 1.7 billion to practically yesterday. They include all of the types, plutonic, volcanic, sedimentary, and metamorphic. The rocks occur in nearly all the colors of the rainbow, sometimes in a single outcrop (google Death Valley's Artist Palette if you want to see what I mean). And in most parts of the park there is no vegetation or soil to obscure their complicated structures and relationships.
It's hard to imagine a more dramatic moment for the two elements to intersect. The sun was low in the sky, the rocks were wet from the recent rain storm, so the colors were intensified and the rocks seemed to glow with an inner light.

The rocks we were looking at were part of the Mio-Pliocene sediments and ash/lava flows of the Furnace Creek, Funeral, and Artist Drive formations. They accumulated in a fault basin not totally unlike the present-day Death Valley graben. There were ephemeral lakes, alluvial fans, floodplains, and volcanoes. The plains probably supported a rich fauna of camels, horses, mastodons, birds and predatory cats, who left their tracks in similar-aged rocks elsewhere in the park.
It was a dramatic moment, but as with so many such moments, it was fleeting. The clouds closed in again, and we thought the show was over, except that a few moments later while we drove the highway north of Furnace Creek, the skies opened up one more time to reveal a brilliant rainbow (see the opening if you somehow missed it!). The moment felt perfect.

Addendum: Since we are talking the incredible fossil record of Death Valley, there is news this week of some horrible human beings who have stolen some of the precious fossil trackways I mentioned. I can only hope that the pictures of the probable thieves will lead to arrests and convictions. More information can be found here:

Stepping From a Valley Floor into a Mountain Range: Travels in Death Valley

To me, one of the most stunning things about exploring Death Valley is the abruptness of the landscape. There are no gentle transitions. You are either on the valley floor, or you are on a mountain. There is no in-between. I'm hard put to think of another place in the world where you can stand on a valley floor and place your hand on a mountain slope. It's just usually not the way of things.
But Death Valley is like that. The main valley is more than a hundred miles long, and 10 or 15 miles across. It's a place of wide open vistas that extend for miles. But if you approach a mountain range like the Black Mountains between Badwater and Furnace Creek, you walk up the gentle slope of an alluvial fan, and then you are stopped by the mountain. Because of the active fault scarp, it rises like a wall straight up out of the ground.
We had come down onto the floor of Death Valley after looking at the diversion of Furnace Creek into Gower Gulch, hoping to get some insight into the effects of flooding a small canyon with the debris and mudflows from a drainage area of 170 square miles. It was pretty awe-inspiring. In the 70 years since the diversion, Gower Gulch had scoured its channel through the Black Mountains, and eroded a deep channel into the surface of the Gower Gulch fan. There's a 25 foot high dry waterfall at the entrance to the canyon, but a trail clings to a narrow terrace of the old alluvial fan to the left (above). It's not hard to explore the narrow canyon above.
There was still a thin stream of water flowing through the canyon, a small remnant of the flash flood that had thundered through the canyon the previous night (Death Valley had just experienced a night of record rainfall for the date, 0.62 inches; of course we were camped out in the open). The debris had covered the highway just downstream.
It's a steep and rugged canyon, one of many that begs exploration by curious people. Treasures are to be found in these canyons...old mines, colorful rock exposures, fossils, and elusive life: Bighorn Sheep maybe, or a Kit Fox. Who knows?
In the end, it's all about the landscape itself. Naked rock exposures and faults. Alluvial gravels. Stepping from a valley floor into a mountain range in one step. There's no place in the world like this...

Sunday, March 26, 2017

Travels in Death Valley: the Strange Story Told By a "Rock"...

A beautiful collection of colorful rocks lie scattered across the surface of an alluvial fan in Death Valley National Park a few miles south of Furnace Creek. There is a piece of vesicular (full of holes) basalt on the lower right, next to a piece of gray limestone. One might be just 10 million years old, while the other may be 300 million, containing the remains of long dead and extinct organisms. At the top left, a piece of orange-brown sandstone, possibly deposited on an ancient ocean shoreline, or maybe a lakeshore in a long-ago desert, maybe even a sand dune. Perhaps a piece of granite is in there somewhere, a rock that cooled four or five miles deep in the crust. What a long journey it had before it was exposed by erosion and carried down the desert wash! And then there is...wait...what is that at center left? That's no conglomerate! Well it sort of is, but isn't natural is it? That's a piece of pavement. What's going on here?
It's not a story that appears on National Park Service interpretive signs, and in fact I think the park service would rather that people not explore the particular canyon at all. It's sort of unstable, as in vertical walls made of loose and cracked chunks of claystone. And like the piece of asphalt pavement on the alluvial fan surface, it's not natural either. This canyon didn't exist 75 years ago.

Gower Gulch used to be a minor drainage in the Furnace Creek Formation badlands near Zabriskie Point which debouched onto the floor of Death Valley, forming a small alluvial fan. Badwater Road crossed the fan, which consisted of mostly fine-grained materials like silt and clay.

The problem is that nearby Furnace Creek drained a much larger region than Gower Gulch (170 square miles versus 2 square miles), and was prone to violent flashfloods and mudflows that damaged facilities at the Furnace Creek Resort about five miles downstream. Around 1941 someone thought to blast through the low ridge that separated Furnace Creek and Gower Gulch, forcing the entire drainage to flow through the badlands and onto the Gower Gulch fan downstream. The diversion caused profound changes upstream and downstream.

At the diversion point (above), the flash floods cut through the soft siltstone and shale like a hot knife through butter, cutting 40 feet or more in seven decades. The floods carry a heavy load of coarse-grained debris and gravel that acts as an abrasive on the channel floor. The canyon changes year to year as each flashflood causes slopes to be undercut, causing rockfalls and slope failures.
It's upstream where serious damage to the road occurs. The diversion caused a sudden steepening of the Furnace Creek channel, and the faster moving floods have eroded the channel in an upstream direction, a process called headward erosion. The deepening of the channel is apparent as far as two miles upstream, and in numerous places it has encroached onto Highway 190, washing away some of the pavement, and incorporating the fragments into the alluvial fan deposits downstream (as in the first picture above).
Downstream, the road damage occurs in a different way. The alluvial fan used to receive fine-grained silt and clay in relatively minor floods that did little damage to Badwater Road. Now the flashfloods are on steroids, so to speak, with more water, more debris, and far more speed. Badwater Road is regularly overwhelmed, as it was on the day we visited, with mudflow deposits. Boulders can sometimes be sizable. For example, check out the two fragments on the fan in the picture below. How big do you think they are?
Here's your answer: pretty big.

Death Valley is a monument to geologic changes over billions of years, but it is also a dynamic environment where geologic change happens on a daily and yearly basis as well. We saw plenty of evidence during our February trip.