No, It's Not Erupting...and Probably Won't Any Time Soon: Mt. McLoughlin in the Oregon Cascades

There is a grand and momentary sight to be had if you are driving south on Interstate 5 about seven or eight miles north of Medford, Oregon. If the weather is clear when you round the last bend before the Rogue Valley, a beautifully symmetrical volcano comes into view. It is called Mt. McLoughlin. It's really quite dangerous for geologists to drive on this highway because of our tendency to swerve and hit the brakes the moment we see the volcano and start scrabbling around trying to find the camera. I get honked at a lot by angry truckdrivers all the time around that moment.

Luckily for me, Mrs. Geotripper was riding shotgun today, and I knew the corner was coming up. She got the camera ready ahead of time and was able to snap a couple of pictures. With the news of volcanoes erupting around the world at the moment (check out Mt. Etna in Italy and Krakatoa in Indonesia, for instance), it's not surprising to consider for a moment that McLoughlin looks like it's erupting. What we are seeing here is clouds forming as warmer air masses are blown upslope into colder air around the summit. The cooler temperatures cause the humidity to jump and condensation forms the clouds around the volcano summit. Sometimes the clouds are more lens-shaped (lenticular), giving rise to legends of UFO landings and aliens.

Mt. McLoughlin is 9,495 feet (2894 meters) in elevation and can best be described as a composite cone, as it is in part a basaltic shield with a prominent summit cinder cone and andesite flows. It has not erupted in the last 20,000-30.000 years and thus appears to be low on the list of recognized hazardous volcanoes. From some angles McLoughlin is a deceptively symmetrical cone. The summit has been deeply carved by glaciers.

Mt. McLoughlin is soon lost among the trees, buildings, and powerlines of Medford. It's not a particularly worrisome volcano although it is capable of wreaking havoc if the unlikely ever happens. But if you keep driving south on I-5, there are highway signs pointing to a volcano, or more correctly, a caldera, that is not visible at all from the freeway. It's Crater Lake, and it is a much more dangerous volcanic complex than McLoughlin. It erupted catastrophically only 7,000 years ago. And farther south still is Mt. Shasta. It looms menacingly over Northern California, and we'll have a short look at it in our next post.

POSTSCRIPT: I found out I had some aerial shots of McLoughlin from a flight I took in 2005. Here's one of the best. We were east of the volcano looking west. The glacial cirques are clearly visible...

The Many Sides of California's Incredible Composite Cone Mt. Shasta

Hotlum Cone and Shastina, the two youngest cones of Shasta are seen here from the north on Highway 97

California has a lot of incredible volcanoes, but looming above them all is Mt. Shasta, the huge composite cone that rises above the mountains of Northern California. At 14,179 feet, it towers over all but a few of the highest peaks of the Sierra Nevada, but none of them are close by. It is more than a mile higher than any other nearby peaks. I and my students have been traveling around it the last two days, and we've seen it from every side.

From the south it was largely hidden by the smoke from the recent wildfires, but we drove up the Everritt Memorial Highway to the 8,000 foot level at Panther Meadows. The barren valley once hosted a ski resort until folks realized the lack of trees in the area was because of the constant avalanches. The ski area was moved, but the road remains, and serves as a high trailhead for summit attempts.

The Sargent's Ridge and Misery Hill cones of Mt. Shasta. These cones are older and more deeply eroded.

A careful study of the ridges and valleys reveals that there have been more than one "Shasta". At least five volcanoes have developed over the Shasta magma chamber, but most of them have been removed by erosion, explosion and avalanche. Only the highest cone, Hotlum, and the satellite summit of Shastina seem untouched by serious erosion. They are both less than 10,000 years old, and Hotlum has continued to erupt at intervals of several hundred years.

From the northeast, Shasta is highly symmetrical. That large snowfields remain in the fall season is evidence of the presence of glaciers. Shasta has at least five of the them, and Whitney Glacier is the longest glacier in all of California, at two miles.

The peak shined bright and clear in the morning light, but by this evening, it was shrouded in clouds and lightning was flashing in the skies above. The mountain, a so-called composite cone is a mountain of many moods.

I'm pretty sure I don't want to see the mountain angry...

America Has Other Volcanoes: Airliner Chronicles Visits Mt. Hood

The tragic and yet fascinating activity on the Big Island of Hawai'i has focused attention on volcanism in the United States, and has served to remind us that Hawai'i isn't the only place in the country that has to face up to the hazards of living in the shadow of dangerous mountains. I traveled to Washington by plane last week and was lucky enough to capture images of several of the volcanoes of the Cascades. We looked at Mt. Rainier first, and then at California's largest yet little-known volcano, Medicine Lake Highland. I really wanted to show some shots of St. Helens but we flew right over it, so I cheated and used some shots from 2006. But I wasn't disappointed by Oregon. The face of Mt. Hood was still illuminated by the rapidly setting sun.

Mt. Hood is the headache for emergency planners in Portland and the small villages south of the Columbia River. It is the highest mountain in Oregon at 11,249 feet (3,429 meters). The upper slopes are extremely rugged and steep and as such present a serious threat of debris avalanches similar in nature to that which destroyed the summit of Mt. St. Helens in 1980. The scar of the most recent avalanche can be seen on the right side of the summit in the picture below. The slide took place about 1,500 years ago. The prominent spike of rock in the alcove is called Crater Rock, and it is the remains of a lava dome that erupted around 1781. An earlier avalanche around 100,000 years ago removed the north flank of the mountain and flowed down Hood River Valley and across the Columbia River.

The thick mantle of snow presents the other serious hazard, that of lahars, or volcanic mudflows. The fluid masses have reached the outskirts of Portland in the past, and some lahars have occurred in recent years even though no eruption took place.

Living near volcanoes doesn't and shouldn't mean living in constant fear, but it is important to be aware of the potential threats where you live, and an understanding of what you will need to do in the event of an eruption. And because of all the crap roiling around on the internet, get your information from the geologists who work for the U.S. Geological Survey or state surveys in your area. Always be aware of the potential of exaggeration in the media, because even if they present good information, it will be cloaked in clickbait-style headlines that they utilize to get attention these days.

Meanwhile, the plane continued southward, and another volcano or two could still be discerned in the fog and mist. My mention of the Airline Chronicles refers to my first blog series that started way back in 2008. Some more information on Mt. Hood is available at  https://pubs.usgs.gov/fs/2000/fs060-00/.

The Amazing Disappearing (and Very Dangerous) Mountain: Mt. Rainier

Yes, disappearing. In two senses, one rather personal. Mt. Rainier is actually one of the most obvious, most visible mountains on planet Earth. At 14,411 feet (4,392 meters), it towers over western Washington, and in clear weather can be seen from more than a hundred miles away in some directions. In clear weather, that is...

I was in Washington just a week ago, part of my eclipse-related journey, but in four days, I saw not one little bit of the mountain. It was mostly overcast, or I was in one of those spots where the peak simply wasn't visible. The peak had disappeared and it was kind of frustrating!

And then there was our summer field studies trip back in June. We had plans for exploring the Mt. Rainier area then as well, but the heavy snows of last winter had not yet melted much, so we only managed a single stop within Mt. Rainier National Park (near Chinook Pass), with only a single view, and no trails that we could explore (although there was an epic snowball fight). That stop makes up the first two pictures of this post. I had to dig into the photo archives to find some other views of the mountain. The one below is from our 2014 exploration of Canada that included a short stop at Rainier along Sunrise Ridge (below).

Mt. Rainier is the tallest volcano in Cascades Range, and is exceeded in volume only by Mt. Shasta. Because it is by far the tallest mountain in the Pacific Northwest, it is completely covered by the largest mass of glacial ice in the lower 48 states, about a cubic mile (I read somewhere that it contains half of the all the glacial ice in the lower 48, but I can't find the source and would welcome any corrections from those who know such things). Aside from the "normal" threats that volcanoes might present to a given region (lava flows, ash flows, and that sort of thing), the snow makes the mountain far more dangerous. It's not hard to imagine why: any small eruption would melt a vast amount of ice, forming volcanic mudflows called lahars that are capable of flowing for many tens of miles, and threatening many of the cities along the southern part of the Puget Sound. The entire city of Tacoma is built on a mudflow that thundered down the mountain 5,000 years ago. The last major eruption occurred around a thousand years ago, although minor activity was noted several times in the 1800s.

The reason I mentioned "disappearing" in two senses has to do with the effect of the ice on the mountain. The volcano is being dismantled. Glaciers are a major force of erosion, especially when the underlying rock has been weakened by chemical weathering related to the hot acidic fluids that circulate and attack the mountain from below (hot springs exist around the summit where the steam has excavated miles of ice caves). The glaciers have scraped away the rock around the original summit, which has also collapsed in several large debris avalanches. In other words, the mountain once stood as high as 16,000 feet, which would have made it the highest mountain in the lower 48 states by far.

My favorite pictures of Mt. Rainier both involved flights. I was returning from a geology trip in Italy a number of years ago, and our flight path took us right over Rainier, giving me the awesome perspective seen in the picture above.

On a different flight from Seattle, we took off just after sunset and I didn't expect to see anything, but the faint twilight allowed the mountain to glow blue, and I got the rather ethereal other-worldly view seen below. The color is the way the camera recorded it (I didn't play with the contrast or color).

Mt. Rainier is a place I would very much like to get to know better.

When Life Gives You a Single Point of View, Milk it For All it's Worth: Crater Lake in June

It never fails. I secretly control the incidences of drought and flooding in the western United States. How? By scheduling our summer field studies a full year in advance. The proof? Every time I schedule a Southwest trip, the climate changes to long-term drought, and it is a hot summer. Every time I schedule a trip to the Pacific Northwest, the drought breaks and we have record snowfall in the winter that doesn't melt until well into the summer. This was the case in 2011, our last northwest trip, and it was the case again this summer, in 2017.

In 2011, we saw that Crater Lake was snowbound, so we didn't even try to go there, heading into Newberry Crater instead. Even though somewhat lower, it was buried in snowdrifts as well. It had now been more than a decade since I had laid eyes on Crater Lake, so I planned the visit anyway, even though most of the roads were closed, and we would have to backtrack 80 miles off our trip route.

The only problem with having a single point of access and only a few parking lots plowed of snow was that only so many people could be accommodated in the park at a time, and June's massive heat wave was just getting started. People wanted to cool off, so they headed up into the mountains to Crater Lake. As a result spent 45 minutes in line at the entrance station, and our four vans were on their own for parking. We radioed each other to meet up at a rendezvous point near the rim once parking site was secured. So it was that instead of exploring a national park, we had the singular opportunity to view it from just one part of the rim.

And yet, what a sight it was! Just the dimensions are stunning. The lake is six miles across and 1,949 feet deep (542 meters), the deepest in the United States, the second deepest in North America, and the ninth deepest in the world (Baikal in Russia is the winner of that race, at 5,387 feet, or 1,642 meters). The deep blue color of the lake follows from the clarity of the water, which has been measured as deep as 175 feet (53 meters). It's not just the reflection of the sky above (note that the sky is lighter than the lake surface). The clear water absorbs the longer light waves at the red end of the spectrum, but scatters and reflects the shorter waves at the blue end of the spectrum.

The "crater" of Crater Lake is not a crater in the usual sense. It is a world-class example of a caldera, a volcanic feature that develops when a huge volume of ash explodes out of volcano, and the summit sinks into the void left behind. It was an unimaginable catastrophe. In the space of a few hours or days around 15 cubic miles of ash and debris were blasted into the atmosphere from the summit area of Mt. Mazama, the name given to the former volcano that became Crater Lake. What had once been a volcano as tall as 12,000 feet was now a smoking ruin with a rim barely exceeding 8,000 feet. The bottom of the caldera was another 4,000 feet lower. The ash was spread across the western United States and Canada, providing a crucial dating horizon for archaeologists (the ash has a unique chemical composition that can be identified in dig sites).

The lake itself, of course, came later. It is estimated that it took around 700 years for the lake to fill the depression to the level of the current day. There is no inlet or outlet. Water comes from snow and rain, and the level is balanced by evaporation and seepage (there are numerous springs around the flanks of the volcano). Fish are not native to the lake, but several kinds were introduced over the years. They don't do particularly well because of the purity of the water (there are few nutrients to support a food chain).

The Crater Lake caldera is young in the geologic sense, having erupted 7,700 years ago (+/- 150 years). Think about that: the ancestors of the indigenous people of the region saw and experienced this event. Their oral histories of the Klamath people recall the event. How many cultures in in today's world have collective memories that date back that far?

One might wonder if any eruptions from recorded history can match the violence of the Mazama eruption 7,700 years ago. It turns out there is. In 1815, Tambora, a 14,000 foot high volcano on the island of Sumbawa in Indonesia exploded with a fury equivalent to that of Crater Lake. The summit collapsed into a caldera in the manner of Crater Lake. After 200 years, a lake has begun to accumulate on the caldera floor.

Tens of thousands of people on the island died from the eruption itself or starvation later (all vegetation on the island was destroyed). So much ash was blown into the atmosphere that the climate cooled to the extent that snow fell during the summer months over much of the northern hemisphere. Famine contributed to hundreds of thousands of deaths around the world.

When we visited the park, the lake was still covered by snow, and crowded with tourists, but none of that could obscure the incredible story told by the rocks and water. The Cascade volcanoes are capable of great violence. The eruption of Mt. St. Helens in 1980 killed around four dozen people and did a billion dollars in damage, but the volume of that eruption was only about 1/60th the size of the eruption of Mazama 7,700 years ago. It's hard to imagine the effects of such an eruption in today's technological society. Would we be talking about it 8,000 years later?

Just How Big is Mt. Shasta in Northern California? Getting a sense of scale...

Mt. Shasta is a big mountain. It becomes visible from upwards of a hundred miles away. Topping out at 14,180 feet (4,322 m), it has the greatest volume of any Cascades stratovolcano at around a hundred cubic miles of lava flows and ash (the less visible shield volcanoes like Medicine Lake Highland are larger however). Driving north on Interstate 5, the mountain edifice takes on the very definition of "looming".

On our recent journey through the Pacific Northwest, Mt. Shasta was our first lecture stop. We drove up the flank of the mountain to an elevation of 7,000 feet or so at Bunny Flat, where we were stopped by snowdrifts...in late June. It's been a wet year!

It's hard to get a true sense of scale sometimes when observing really big mountains, but my camera has a pretty dandy zoom lens, so I had a bit of fun with it. In the picture above, note how the center of the picture is completely snowbound, except for three rocks near the top of the ice slope. I zeroed in on it.

In the photo above, we can see those three large rocks a bit more clearly. Keep in mind that we are already 7,000 feet up the mountain. There is more than a mile of mountain above us.

Zooming in once more, we can see that there is more than just three big rocks on the slope. It's hard to get a sense of how big they might be, except that at this scale we can see some more very small black dots scattered about the slope. What could they be?

At the highest zoom (60x), the small dots resolve into human beings. It was a hot day in the valley, so a lot of people were up on the slopes of Mt. Shasta keeping cool. And yes, Shasta is a very big mountain.

About to Hit the Road Again! There are Volcanoes in my Future

And it's been way too long locked away in an office and laboratory and lecture hall. I'll be hitting the open road with my students on an exploration of California's Cascade volcanoes for the next five days. We'll be seeing Mt. Shasta, Lassen Peak, Medicine Lake Highland, and Lava Beds National Monument. All in all, it's a fascinating corner of the Golden State. I may actually have some web access along the way, so I'll try to send some dispatches.

You've Read About Them: How About Seeing Them in Person? California's Volcanoes Field Studies, Sept. 22-26, 2016

Mt. Shasta, the second tallest and most voluminous volcano in the Cascades

I write so much about my travels around the American West and elsewhere, and some might wonder where I find the time. Well...I tend to have a group of students with me. Geology, perhaps more than any other science, is best learned in the field, and our school recognizes the importance of field experiences.

Lava Beds National Monument

The community college system in California is of course one of the best alternatives for beginning a college education, a gateway to transferring into universities, but we also recognize lifelong learning as a part of our mission. Education doesn't just end with a degree. Professionals in one career can benefit from courses in related disciplines as a way of improving their job performance, or advancing up the pay scale. And all citizens can benefit from becoming better informed on the political issues of the day, such as climate change, or energy development (pulling some examples from geology).

Medicine Lake, glacio-volcanic lake occupying a large caldera.

With this in mind, I wanted to let my Modesto-based readers know about some great field studies trips coming up this fall. On September 22-26, I'll be teaching Geology 185, the Geology of California's Volcanoes. We'll be exploring Mt. Shasta, Lava Beds National Monument, Medicine Lake Highland, and Lassen Volcanic National Park, as well as Castle Crags and McArthur-Burney Falls State Parks. We will be camping at Woodson Bridge State Park the first night, spend two nights at Lava Beds National Monument, and the last night at McArthur-Burney Falls State Park. There will be hiking and caving opportunities, and some simply incredible scenery among some of the youngest volcanic features in the western United States.

Jot Dean Ice Cave. The ice persists in the cave year-round.

If this sounds intriguing, you can find more information at http://hayesg.faculty.mjc.edu/Cascades_field_studies.html. California residents pay the normal tuition rate (2 semester units), but the rate is higher for out of state participants. The $90 fee for the course covers the van transportation and fees at the various parks and campgrounds. The students provide their own food (we'll have stoves and fuel). For my local readers, we'll have an organizational meeting on Thursday, September 8 in the Science Community Center at Modesto Junior College, room 326, at 5:30 PM. Contact me if you have questions.

Lassen Peak and Manzanita Lake. Lassen erupted in 1914-15, while Manzanita Lake formed behind a debris avalanche about 300 years ago.

This isn't our only field studies opportunity! Watch for other announcements soon.

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!

Geotripper Finds Rocks in the Pacific Northwest! All is Well

Diablo Reservoir and Colonial Peak in North Cascades National Park

I admit to being just a little bit snarky in some of my recent posts concerning the paucity of rocks seen on my latest journey through the Pacific Northwest. Seeking out the rainforests was one of our main goals on this trip, and I thoroughly enjoyed my visits to Humboldt Redwoods, the Hoh Rainforest of Olympic National Park, and the forests of British Columbia. One the other hand, it is true that rocks were in short supply for the first part of our journey. That sure changed in the last few days!

Kangaroo and Vasiliki Ridges near Washington Pass, east of North Cascades National Park

I will probably write a series of blogs about our vagabonding across the Pacific Northwest, but one thing to point out is that we were attempting to explore new territory, and that included the North Cascades, a big mysterious blank area on the map of my personal geography. I've been around the mountains and seen them from a great distance, but before yesterday I had never seen them up close.

Early Winters Spires at Washington Pass east of North Cascades National Park

We pulled into the campground at Newhalem in North Cascades National Park, or more properly, Ross Lake National Recreational Area. The park itself is the remote wilderness in the peaks above the Skagit River. We then took a late afternoon driver to Washington Pass on the east side of the park. It was simply stunning! I've down a lot of traveling and seen many wonders, but my breath can still be taken away by an incredible view.

Mt. Baker and Boulder Creek (I wonder how the creek got its name?)

The next morning was a short exploration of the Baker Lake area, and one of the most interesting of the Cascades volcanoes, Mount Baker. It is one of the most active of the chain, with some minor eruptions in the 19th century. It is second only to Mt. Rainier in the volume of ice coating its summit.

The glaciers of Mt. Baker, lahars just waiting to be released.

It's been a fascinating trip (that isn't quite over yet). I'm looking forward to sharing some interesting geology in coming weeks.