Vagabonding on Dangerous Ground: Danger Follows Us Home (As it does all of us)

Mt. St. Helens from Silver Lake

We have finally reached the last few days of our meandering journey through the lands influenced by the Cascadia Subduction Zone. We spent several weeks out there, checking out the landscapes threatened by a possible magnitude nine earthquake. Although the hazard has been recognized for quite a few years, there was a media storm over the summer that brought the dangers into focus for the people living in the coastal zones of the Pacific Northwest. We were on our vacation anyway, traveling up the coast, but our search for beautiful scenery became an exploration of geological landscapes threatened by earthquakes, landslides, tsunamis and floods.

After many days in Oregon, Washington and British Columbia, we were on the homeward road, traveling hundreds of miles a day, knowing that issues at home needed attention. It didn't leave much time to investigate the other danger facing those in the northwest: volcanic activity. We got to see Mt. Baker for the first time, and Mt. Garibaldi, but Mt. Rainier and Mt. St. Helens were hidden in the clouds (we had a brief view of St. Helens from Silver Lake; see the first picture). Mt. Hood, the Three Sisters, Crater Lake, and all the other Cascade volcanoes were hidden behind the forested ridges. We couldn't see them from the freeway, and we had no time for detours.

But then we crossed back into California, forded the Klamath River, and surmounted a ridge where a gigantic mountain came into view. It was Mt. Shasta (14,179 feet / 4,322 meters), one of the southernmost volcanoes in the Cascade Range (Lassen Peak is down that way too). Although it is a few hundred feet shorter than Mt. Rainier, it has much more volume. Not only is it the largest volcano in the Cascades, it is the second most active, exceeded in that department only by Mt. St. Helens. Eruptive activity occurs every 600 years or so. The last eruption was an ash explosion 200-300 years ago, possibly witnessed in 1786 (this is disputed; wildfires can look much like volcanic eruptions).

Like any active volcano, Shasta is dangerous. It's not just lava flows (that Hollywood staple), but potential ash flows, and volcanic mudflows (lahars), made all the more likely by the presence of California's largest glaciers around the summit. Many times the lahars occur without eruptive activity (at least 70 times in the last 1,000 years) as glaciers melt in the warmer seasons. Most of the towns near Shasta are built atop lahar deposits (around 10,000 people live in the immediate vicinity of the volcano). 

The pictures in this post are unique in one sense; they were mostly taken from a moving vehicle (by Mrs. Geotripper; I was trying to concentrate on driving). We had come 250 miles already, and had another 250 before we would get home, so we just didn't have time to linger. Driving does give one time to think, though, and I was thinking about the nature of geologic hazards.

We had just spent weeks traveling through a region that could potentially be devastated by an entire buffet of disasters. And yet millions of people live there, either unaware or willing to take the chance in order to enjoy the amenities of living in a coastal paradise, or someplace incredibly green and scenic. I felt no sense of relief from getting out of that danger zone because I understood that any one of those disasters had a very small chance of taking place while I was there. Even if something had happened, we were stocked up and prepared to be on our own for upwards of a week or more. But the clock was ticking, and the longer one stays, the greater likelihood that something bad will happen.

But a geologist's perspective provides little comfort. Going home to familiar ground was no protection from geologic disaster, whether sudden or over decades. I live in a flat and (dare I say it?) boring place, and yet I face geologic disasters every day. I live only about fifty miles from the San Andreas fault, and just twenty or thirty miles from lesser-known but active faults. I live next to a major river that is prone to flooding every few years. My town is just eighty miles or so from a rhyolite caldera that is more active than the "supervolcanoes" of Yellowstone National Park. And for the last four years we have been suffering through an unprecedented drought unlike any ever faced by modern-day California (although precedents exist in the recent geologic past). There's no escaping the Earth, and no one is immune from disaster.

Sutter Buttes from the Sacramento National Wildlife Refuge, the remnants of a Cascades-style volcano in the Great Valley of California. Wait, what? A volcano in the Great Valley???

As we drove through Sacramento in the late afternoon, we could see the very strange skies produced by an out-of-control wildfire in the Coast Ranges. It was too close for comfort, and even as I write this fires are burning very close to the homes of friends in the Mother Lode (100 square miles and only 10% contained), and one of my most precious of landscapes, Kings Canyon in the Sierra Nevada, has gone up in flames (200 square miles already incinerated). In my life, these places will be forever changed, and for the lives of those in the path, their lives will be forever changed.

If geology and earth science teaches us anything, it is that we can't avoid disaster no matter where we go. You don't like earthquakes and volcanoes? Fine. Move to Kansas and enjoy the tornadoes, heatwaves and droughts (I used to say Oklahoma, but they have more earthquakes now than California). Move to Florida and enjoy the hurricanes and the unstoppable rise of coastal flooding. Every place on Earth that I know of faces some kind of event that is incompatible with human existence. And in a strange way, that's what makes us human: we evolved in a dangerous world, and occasionally we are reminded of this in tragic ways.

So how do we respond? Being the teacher that I am, I say the first priority is to educate yourself. Learn what geologic forces influence the place where you live. Learn what the real chances are of such events (don't depend on sensationalist sources in the media or the internet; they want viewership, and aren't really interested in actually educating anyone). Use the resources of the U.S. Geological Survey, or your state geologic surveys (except Oklahoma; for a long time the government there didn't allow the geologists to say that the earthquakes were man-made). Once you know what the threats are in your area, ask yourself what you would do to protect yourself if they were to happen today. Are you prepared? Can you make it through several days or a week or more without water, power, communications? Or the internet? What have you done to be ready? Or, will you be one of the many who will have to wait for the arrival of government assistance?

Am I trying to make you paranoid? Not at all. Paranoia comes from ignorance. If you know what could happen, and you have a plan, you've got the best possible chance to be okay. I can only relate the story of the time I came closest to death. It was two years ago on the Colorado River in the Grand Canyon. Because the river emerges from the deepest parts of Lake Powell, the river is at a constant 47 degrees or so, even when the ambient temperatures in the desert environment exceed 110 degrees. Hypothermia is one of the greatest dangers facing any river rafter. I was anxious about the possibility of a raft flipping in one of the rapids, because more than a few people have died in such circumstances. I worried, but I also practiced in my head, over and over, what I would do if it happened. And I never went into the river without a life preserver.

And of course it happened. We had come through dozens of huge rapids, and one could say that I was almost complacent as we approached Crystal Rapid, one of the two most violent rapids on the river. But the boat flipped in a heartbeat and I was in the river (see the whole story here). Knowing myself, I would have expected to panic, but the mental training took over instead. Although I was in the middle of watery chaos, I was able to get to the overturned raft, which made me easier to find, and I was positioned correctly when I started bouncing off boulders in the river. I was okay in the end, though very shaken. And it was because of the preparation and training provided me by my fellow travelers on the river.

And that's the message I leave with you at the end of this latest blog series. We all live on "dangerous ground". There is no place where we can escape the normal processes of the Earth. But we can choose where to live and what dangers to face, and prepare accordingly. And we can take care of each other when the disasters come.

I hope you've enjoyed the journey! I'll be compiling all the posts in one place soon.

Whispers and Echoes from the Past, When Half My DNA Visited Yosemite National Park

While my "Vagabonding on Dangerous Ground" journey took me far north of my usual haunts in the Sierra Nevada, I had an unexpected encounter with Yosemite National Park while I was gone. We had a brief visit with my mom as we drove home from our long trip. While there, I saw an ancient looking leather booklet, one of those little photo/scrapbooks that were popular in the days when pictures were printed on paper. It was full of pictures of half my DNA visiting Yosemite National Park in the early 1940s. My love for Yosemite is literally in my blood!

The "half DNA" of course was my mother when she was just a few years old. As I flipped through the photographs, I realized that I have been standing in these same places, snapping pictures of my own. It was possible to put them side by side. I wondered to myself, how has Yosemite changed in those 73 years? And more importantly, how has Yosemite NOT changed?

The most noticeable difference is the vegetation. Trees that are in some pictures aren't in others. That's not much of a surprise, given the fact that many trees can grow to maturity in that time period. The man-made structures underwent changes as well. The Tunnel View Parking Lot (in the top picture) was completely renovated and rebuilt just a few years ago. The "Swinging Bridge" at the Swinging Bridge Picnic Area (below) no longer swings. It was replaced by a more stable pedestrian bridge a couple of years ago. The cute little girl on the left in the picture is mom.

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Other changes are more subtle, at least in slightly fuzzy photographs from nearly three quarters of a century ago. A number of serious geologic events have taken place, including three or four of the biggest rockfalls and debris avalanches ever witnessed in the park. I even witnessed one of them, when a large slab came off the face of El Capitan in 2010. The Ahwiyah Point rock fall in 2009 permanently changed the appearance of Half Dome, and the 1996 Happy Isles rock fall did the same to the cliffs below Glacier Point. Four "hundred-year" floods scoured the river channels in the valley in the last 50 years or so, washing away buildings and camp facilities.

The things that didn't change are the things I realized were important. Yosemite National Park is a treasure, and the idea of preserving it for future generations was America's best idea, as the Ken Burns documentary pointed out in beautiful fashion. In one sense, Yosemite is where it all started. In 1864, Abraham Lincoln gave Yosemite Valley to the state of California, with the idea that it be preserved in perpetuity. Later, in 1872, Yellowstone became the first official national park, and Yosemite followed in 1890. The idea of protection and preservation moved forward in fits and starts, with some failures and other hard fought victories. Hetch Hetchy Valley, the second "Yosemite" in the park, was inundated under the waters of a reservoir in 1923. But the ridiculous idea of building a tramway to Glacier Point was stopped cold in the 1970s. The totally crowd-pleasing, but totally unnatural nightly firefall ended in 1968. As I looked through these ghostly pictures of the past, I realized that I've been able to experience the park much as my family did all those years ago. The park has changed, but for the most part the change as been directed towards an appreciation for the natural environment, and not towards profit-making opportunities (although that happens).

My grandparents took my mother to Yosemite in a time and in circumstances that were difficult. It wasn't that the park was inaccessible. The "All-Weather Highway" (Highway 140) was completed in 1926, and other good routes were available. But with the war going on, resources were limited. In those days it would have been quite the challenge for a family of modest means to find their way to the park from Southern California. Although it costs more these days to enter the park, one can stay in relatively inexpensive campgrounds and still have an affordable experience in one of the most spectacular landscapes on the planet. The park can be very crowded at times, but those who are willing to walk a bit can find absolute solitude in the 95% of the park that is officially wilderness land.

Yosemite National Park remains a wonderful place, despite budget constraints and government neglect. The rangers, park personnel, and volunteers do the best they can with the resources they are given. The idea of national parks is still America's best idea, and the parks deserve our vigilance. Threats from those who would profit from our most beautiful landscapes should be stopped, and that's only going to happen if those of us who love the parks keep the pressure on our political representatives. It's never easy, but it needs to be done. I want my pictures of today to compare favorably with the three dimensional total sense immersion photographs and virtual reality images that will be taken by my grandchildren 75 years from now.

If you want to be involved, join the Yosemite Conservancy. Most national parks have a natural history association that fights for the good of the parklands. They deserve your support as well.

Vagabonding on Dangerous Ground: Playing Hide and Seek with a Sleeping Monster

Mt. Baker and Boulder Creek upstream of Baker Lake Reservoir

There's something about traveling through the Pacific Northwest that I may never become accustomed too: the deep, deep forests. As a child in the scouts, living in arid Southern California, I was pretty good at orienteering with a compass and map, but that was predicated on the fact that I could see the mountains around me. That would have been tougher if I had grown up in a rainforest. Every view is of a tree!

And so the struggle to actually see Mt. Baker in the Cascade Range. We had actually traveled around three sides of the mountain in the last two days, but I never got much of a glimpse, either because of the deep forest, or, you know, having to pilot the car without plowing into a tree or a deer. We finally got serious about the effort by detouring onto Baker River Road as we left North Cascades National Park. The road would take us within six miles of the summit as the crow flies. If we couldn't see it from there, we didn't deserve to see it.

This web series was entitled Vagabonding on Dangerous Ground primarily because we happened to be following the coastal parts of the Cascadia Subduction Zone which had become newsworthy over the summer because of a New Yorker article detailing the probable damage from an expect magnitude 9 earthquake offshore. Shaking, tsunamis, landslides, power disruptions and many other frightening events were part of the article. Kind of lost in the whole media affair were the sleeping giants that have always been a visceral threat to those who live in the region: the volcanoes.

In Cascadia the subducting slab of cold oceanic crust and underlying solid mantle material (the lithosphere) are driven into the much hotter asthenosphere, a "mushy" layer in the mantle that is partly molten. The interaction of the slab, water from the oceans, and the hot mantle rocks causes melting of some of the continental crust, forming magma that rises through the crust as a series of plutons. When they cool before reaching the surface, they will form visibly crystalline rocks like granite or diorite. When they reach the surface in a molten state, magma mayhem ensues.

The molten flows of lava that Hollywood seems to love the best are often the least serious problem during an eruption of a Cascade volcano, if they occur at all. More often any lava flows will melt prodigious amounts of snow and ice, producing volcanic mudflows (lahars) that can flow for tens of miles, causing damage at great distances from cone. In ancient times lahars could strike without warning from an eruption that couldn't be seen from within distant downstream canyons.

Some lahars aren't even associated with volcanic eruptions. They can be triggered by landslides on the upper reaches of the steep cones, or by unusually high amounts of glacial melting (water trapped under the glacier may burst out all at once). Mt. Baker has the most snow and ice of any Cascades volcano except Mt. Rainier (and that's a big except, as Rainier has about 50% of all the ice in the lower 48 states). So lahars are the big danger from Mt. Baker.

The other dangers result from explosive eruptions that pulverize the magma and other rocks around the summit of the volcano. The fine dust that results is called volcanic ash. The ash can be so hot close to the volcano that it can be incandescent. Anyone or anything caught in the fast moving ash flows is doomed, plain and simple. An ash eruption hit the Martinique town of St. Pierre in 1902 and killed all but two of the town's 30,000 inhabitants. These hot ash flows are called pyroclastic flows, or nuée ardente, French for "fiery cloud". The good news in the case of Mt. Baker is that relatively few developments are close enough to the peak to be threatened. But there are some.

Hazard areas in and around Mt. Baker in northern Washington

We found great views of the volcano from the dam at Baker Lake, and from Boulder Creek. Boulder Creek also provided a nice view of some lahar deposits as well, possibly from events in 1843 or 1891.

Mt. Baker is one of the youngest of the Cascade volcanoes, having formed mostly in just the last 30,000 years. The last major eruptions took place around 6,600 years ago when large lahars swept down creek valley accompanied soon after by ash eruptions. The 1843 eruption was caused by a hydrovolcanic explosion (groundwater flashing to steam). That event left behind Sherman Crater. In 1975, there was a vast increase in the amount of thermal energy around the summit of the mountain, raising fears of an eruption. The heat subsided somewhat, and everyone forgot about Mt. Baker when Mt. St. Helens exploded just five years later.

Lahar deposits at Boulder Creek near Mt. Baker

We were seriously on the homeward path now. No meandering highways along beautiful coastlines for us anymore. Interstate 5 was going to be our pathway now as we pushed south. But the Cascadia Subduction Zone had one more beautiful surprise for us. We'll wrap up our journey in the final post soon!

Vagabonding on Dangerous Ground: What's East of North (Cascades), A Brief Explore

Our vagabonding trip through the geologically hazardous territories influenced by the Cascadia Subduction Zone was mostly an unrushed affair as we meandered up the Pacific Coast through Northern California, Oregon, Washington and British Columbia. Towards the end, though, were realized we had spent most of our summer on the road and certain duties needed attention before the start of the school year (you know, that whole "writing syllabi, ordering textbooks, and cleaning the lab" kind of thing). So our last few days were very short explorations of some very beautiful places that I must return to as soon as possible. One of those places was the North Cascades National Park Complex (the park itself and two adjacent National Recreation Areas).

Our brief drive included a look at the "gorgeous" Skagit River Gorge and the large hydroelectric dams that utilize the high gradient river to produce a fifth of Seattle's electricity. We took advantage of the extended late-afternoon light to explore a little farther up Highway 20, which took us east of the national park. We had trouble telling the difference...it was just spectacular. We drove to the first summit at Rainy Pass, and saw there was another pass just a few miles way, so we went there too. 

Washington Pass (elevation 5477 ft./1669 m) was truly stunning, especially for a person like me. I've traveled a lot, but often visit the same places over and over, with students along. I enjoy the looks on their faces when they see something they've never seen before, but I don't get that thrill of "the first time" all that often. I got it here!

A short trail led to an overlook of the Liberty Bell and Early Winter Spires, a group of highly jointed granitic towers. There are popular climbing routes among the cliffs. The rocks are part of the Golden Horn batholith, an intrusion of granite dating to 48 million years ago.

Looking south we could see Kangaroo Pass. The rocks on the right side of the pass are part of another intrusion, the much older Black Peak tonalite. It dates to around 90 million years ago. The bowl at the head of the valley is an example of a cirque, the origin point for the glacier that flowed down Early Winter Creek during the ice ages.

The prominent peak in the center of picture above is Silver Star Mountain, with Vasiliki Ridge to the left, and Kangaroo Ridge to the right. The entire ridge is composed of the Golden Horn granite. One might wonder why this glacial valley of granite doesn't display domes like those of Yosemite. It's the joints. They are too closely spaced for exfoliation and dome formation to take place. It gives the entire region a sense of extreme ruggedness, and indeed the highway itself was not completed until 1972, after decades of seeking workable routes over the North Cascades.

The road descends north through the glacial U-shaped valley of Early Winter Creek.  We didn't have time. We turned back and headed down to camp in the Skagit Gorge in the setting sun.

There was one more "never-before-seen-by-me" mountain in the area. We'd be looking for it the following morning.

California's Endemic: Yellow-billed Magpie on the West Campus, Back from the Brink, Maybe? (from Geotripper's CA Birds)

Note: Occasionally the subject matter of posts that I put on Geotripper's California Birds spills over into areas that may be of interest to those interested in the geology I cover at Geotripper. This is one of them, so I've re-posted it here:

California has precious few endemic species of birds. In one sense, this fact seems odd, given the many ecological "islands" in California, isolated environments where evolutionary pressures are the greatest. There are high alpine environments, desert mountain ranges with relict conifer forests, and valleys isolated by high mountain ranges, for instance. I have a feeling that the geology of the state has something to do with it the distribution of birds. There are many environments, but the orientation of the geological provinces is mostly north-south, and routes exist for birds to spread far and wide, crossing political borders into Baja and the Pacific Northwest. There are low exit points from places like the Great Valley and low passes over the margins of the Sierra Nevada. Other vertebrates can't surmount these boundaries the way flying birds can, so the trapped reptiles, amphibians and mammals show a great deal more species variation and endemism (is that a word?).

Endemic species are also vulnerable. Highly specialized species living in a single environment are subject to population disruptions when that environment is altered by the appearance of an invasive species or new disease. We've seen that on a human scale in our state. The indigenous people of the state were almost completely wiped out in the early 1800s by malaria and other diseases, with mortality rates estimated in the range of 90%. Our endemic Yellow-billed Magpies (Pica nuttalli) almost met a similar fate, and only a few years ago.

In 2004, West Nile Virus reached California and the effect on the Yellow-billed Magpie was nothing less than catastrophic. They had almost no resistance to the virus (95% mortality), and their tendency to gather in large flocks made transfer of the virus inevitable. Within two years the population crashed, dropping from an estimated 180,000 birds to 90,000. By 2007, some research suggested that the population had been halved again. Only 5% of the living birds tested displayed any kind of antibody response to the virus. That's an extinction threat.

I have memories of big flocks of the Magpies in our region, and I've not seen anything like them in my travels of the last few years. I was so very pleased to come upon a small flock when I was walking the perimeter of our West Campus on Tuesday. There were a dozen or so birds, and that is probably the largest group I've seen in some time. I saw more of them this evening in my neighborhood as well. I hope it is a good sign. They are gorgeous spectacular birds, and it would be such a shame to lose them.

I can't find any more recent data on their populations. If you know anything, please feel free to contribute to the comments!

Vagabonding on Dangerous Ground: The Geology That Explains Why North Cascades is a Park Divided

Diablo Reservoir below the peaks of North Cascades National Park. The Turquoise color results from fine silt and clay derived from glaciers.

As I described in my last post on vagabonding, North Cascades National Park is the most strikingly beautiful national park I visited but never set foot in. The reasons become immediately clear with a look at the map of the park. There are two roadless sections, the North Unit and South Unit, and they are separated by the Ross Lake National Recreation Area along the Skagit River. And we unfortunately didn't have enough time for extensive hiking.

The human reason for the separation of the two park units is explained readily enough. Most national parks are established for their wilderness, geological, biological or historical values. They are not generally established to praise the engineering works of humankind. There are a series of dams and hydroelectric generating facilities in the Skagit River Gorge, and as such, they are administered as a series of national recreation areas. All of the parks and recreation areas were established at the same time, and are jointly administered by one bureaucracy. Because of the easier access (i.e. actual paved roads), the recreation area receives 750,000 visitors each year. The national park is visited by around 20,000 people a year. It would be fair to say that most of the visitors to the Ross Lake unit are there to appreciate the beauty of North Cascades. From a distance...

It turns out that geology had a lot to do with the circumstances leading to a separation of the two park units. We put dams where they will store as much water as possible, and that usually requires the presence of large rivers and drainage basins. Were it not for a geological event a few hundred thousand years ago, the Skagit River would have not been an appropriate place for a series of huge reservoirs (Ross Lake, for instance, has a capacity of 1,435,000 acre-feet of water. The lake is 22 miles long and extends into Canada). Prior to the ice ages, the Skagit River was a relatively small river, and the drainage did not cross the divide between the two park units as it does today. Instead, the ancient headwaters of the Skagit flowed northward into Canada, becoming part of the Fraser River drainage.

The ice ages put an end to that. A huge lobe of ice flowed south out of Canada, blocking the flow of the upper Skagit. The river backed up into a large lake, and eventually the lake breached the rim at a different location and started flowing west. The meltwater from the glaciers added to the ability of the river to carve downward, and the Skagit River Gorge was quickly cut (at least in geological terms). The river that flowed west was now many times larger, and the Skagit Gorge was too much of a temptation for any dam engineer to resist. Three reservoirs were built, Gorge, Diablo and Ross, and today they provide around 20% of the electricity used in Seattle.

So, today we have one of the most beautiful alpine regions in the Pacific Northwest, and a once small river made far larger by a quirk of geological history. It was a marvelous sight, but there was more. We drove beyond Ross Lake and headed for the high passes beyond. More next time...