Travels in Cascadia: Wanna See a REAL Debate? Talk to an Oregonian about Waterfalls

I was watching the candidate's debate tonight, and there were some interesting exchanges, and the whole future of American democracy hangs in the balance and all, but then I found what a real debate looks like when I googled "Multnomah Falls".

I saw the falls that grace the gorge of the Columbia River for the first time since my childhood last month. We were headed to Seattle to meet our students for our field studies course on the geology of British Columbia and we had stopped in Portland on our way north. I still had an hour or two before sunset so I headed east into the Columbia River Gorge to see the waterfalls that I hadn't seen in something like 50 years or more.

The debate? How do the falls rank against other falls in the United States in terms of height? Sources suggest they are the second highest in the nation, which is off by at least 155 waterfalls. Then there is the qualifier that they are the second highest "year-round" falls in the nation (i.e. they don't dry up for part of the year). But fans insist that Fairy Falls don't run all year. But then there is a different argument, kind of a splitter and lumper sort of thing. How tall is a water FALL? Does one count the single greatest free-fall? Or do you count all the breaks and cascades? Bridalveil Fall in Yosemite is a whole three feet shorter than Multnomah Falls. But it has a single 617 foot drop. The upper fall at Multnomah is a mere 541 feet. The debate rages on. But most of the participants agree it is the highest waterfall in Oregon, and it is a very pretty waterfall. It is the single most visited natural feature in the state, with two million visitors a year.

Two million visitors...given the small size of the park, I'm glad I was there late in the evening and didn't have to contend with thousands of people. The whole scene was quite peaceful and quiet while I was there. But there were signs of geological violence though. Huge rockfall fences lined the trail to the bridge, and scarred trunks showed how close the Eagle Creek Fire came to burning out the park in 2017. In 1995 a 400-ton boulder fell from halfway up the cliff into the pool at the base of the fall, much to the consternation of the 20-person wedding party taking portraits on the bridge. There were minor injuries from splashing water and debris.

Waterfalls are pretty much by definition dangerous places, since the prevailing attitude of Mother Nature is that steep slopes are very much hated and must be removed by one erosional process or another. Which brings up the question of why the slope is there in the first place. A great many waterfalls happen because glaciers have cut steep-sided valleys and tributary streams must fall over the brink. Such features are called hanging valleys. But the Columbia River Gorge was not carved by a glacier. The basalt flows and interlayered sediments were carved by the raging waters of the ice age Spokane Floods and the downcutting of the Columbia River.

Waterfalls ended up being a major part of the geologic story of our journey through British Columbia and northern Washington. Most of them were flowing, but one of the great stories of all of geology was told by a waterfall that wasn't. Those stories are coming up! It's kind of a race to see what's coming first: the rest of the story, or the beginning of the new school semester. We'll see who wins out.

The Disappointing Cape: Land's End and Rock Pillows

Just over 200 years ago, the first expedition of Americans reached the Pacific Ocean after following the Missouri River over the Rocky Mountains and down the Columbia River. Lewis and Clark and their crew arrived in November of 1805, and they knew they could not make the return trip until the winter snows abated.

They explored the area around the mouth of the Columbia for an decent campsite to stay in several months. They ultimately settled on the south side of the river at Fort Clatsop, but for a time they spent a week at "that dismal little nitch" on the north side of the river. They explored around the rocky peninsula that had already been given the name Cape Disappointment by fur trader John Meares who, because of a storm, turned his ship around in 1788, just missing the mouth of the Columbia. The credited discovery was four years later, although we know that history has a serious bias; the river was discovered more than 10,000 years ago by humans.

The peninsula is today a state park, and it has a well-developed campground complex that fronts a wide sandy beach, with a more modest sandy cove on the east side called Waikiki Beach (it memorializes a Hawaiian seaman who perished during a shipwreck).

The winter encampment of the Lewis and Clark expedition at Fort Clatsop was largely a miserable affair with constant hunger and lack of supplies. They had hoped to flag down a sailing ship coming down the coast to trade for supplies, but their fort was a couple of miles from the beach and they missed ships for lack of a good lookout point. One might wonder why they didn't set up camp on the wide sandy beaches of Cape Disappointment. The answer is pretty straightforward: the beach didn't exist when they were there. It was a rocky peninsula as can be seen on their sketched map (below)

The mouth of the Columbia River is a nightmare for shipping. The discharge is more than enough to support even large freighters as far upstream as Portland, but the river carries vast amounts of sand and silt, and the shifting bars have caused vast numbers of shipwrecks. In an effort to stabilize the shifting sand bars, jetties were constructed in 1886. One extends for several miles from Cape Disappointment. Although the rock wall helps to keep the river channel clear, it also serves as a barrier to the southward movement of sand along the coast north of the Cape. The sand started backing up immediately forming the wide flat beaches that can be explored today (see the map below...sand is the yellow unit marked "Qb").

Source: US Geological Survey and https://nwgeology.wordpress.com/the-fieldtrips/pillow-lava-sites-in-washington/pillows-in-the-crescent-formation-cape-disappointment-state-park/

One of the coolest things about exploring Cape Disappointment is the privilege to actually see the rocks. The wave-carved cliffs are not totally covered by vegetation as is so often the case in western Washington. And the rocks are weird. They are not layered, and instead are marked by strange globular masses of what turns out to be weathered and oxidized orange basalt (we would normally expect basalt to be black like the lava flows in Hawaii). How did they get this way?

Note the cormorant for scale (upper left)

When basalt erupts underwater, it forms these globs that are about the size of thick down pillows. It looks like toothpaste being squeezed out and then getting pinched off. Although these rocks are on land today, they were once on the bottom of the Pacific Ocean. They formed in eruptions at the mid-ocean ridge on the seafloor. They traveled like a conveyor belt for hundreds of miles (at the stunning rate of several inches a year) and were scraped off and added to the edge of the continent in the subduction zone that forms the western boundary of the North American Plate in Washington and Oregon. These rocks, the Crescent Formation, are Eocene in age (around 40 million years ago).

Cape Disappointment is a fascinating place to explore (it's neither dismal or disappointing). Watch the weather, though. Not only for the incessant rain, but for fog. It's said to be the foggiest place in the country which helps explain why the peninsula has not one, but two lighthouses.

Cormorant and Pillow Basalt Above Waikiki Beach (but not the one you think)

I'm still on the road so posts are few, but I occasionally get to a computer. Today's picture is a Cormorant flying in front of a wave-cut cliff exposing pillow basalt at Waikiki Beach. I've been writing a lot about Hawai'i of late, so you are forgiven for thinking that this is one the islands, but it's not. It's at Cape Disappointment on the Columbia River in Washington state. It got the name from an event in 1811 when a shipwreck led to the death of a Hawaiian crewmember whose body washed up on the beach here (I don't know why they didn't just use his name).

The pillow basalt is part of the Crescent Formation, a unit that preserves sea-floor sediments and basalt of the ocean crust that was swept into the subduction zone along the west coast of North America. Pillows are globular masses of basalt that form when the lava flows into water. The lava dates from the middle Eocene epoch, about 40 million years ago.

Cape Disappointment is steeped in history, being the last point of solid bedrock along the Columbia River where it flows into the Pacific Ocean. The name came from the failure of early explorers to recognize this spot as the mouth of the Columbia River (hazardous and constantly shifting sand bars made navigation upstream extraordinarily difficult). It was also the place where the Lewis and Clark Expedition finally reached the Pacific Ocean.

The construction of a huge jetty to make navigation on the Columbia River a bit safer caused sand to back up against the rock barrier, forming an extensive beach where none existed before. The site is now a state park and national historical park. There is a nice campground where we enjoyed some rare sun the other day (Cape Disappointment is said to be the foggiest place in the United States).

There are two lighthouses on the peninsula, due to the aforementioned hazards. Around 200 ships were wrecked in the immediate vicinity over the years.

Vagabonding on Dangerous Ground: Putting on a Happy Face at Dismal Nitch and Cape Disappointment

Waikiki Beach at Cape Disappointment. Yes, the cliffs are basaltic like those in Hawaii, but the spot was named for a Hawaiian sailor who lost his life here in a shipwreck (one of many).

How does a place get a name? Cape Disappointment and especially Dismal Nitch seem to just scream to tourists to "please visit us". Both sites sit on the north peninsula where the Columbia River reaches the Pacific Ocean, and both are steeped in history.

The Astoria Bridge (photo by Mrs. Geotripper)

Imagine it's 1805. You've been walking, riding and floating for more than a year through perilous and unknown lands, and your supplies are dangerously low. The food is almost gone, the trade goods are almost gone, and the clothes are literally rotting off your back. You're within a few miles of the expedition's goal, and you know that a ship bearing supplies, clothing and food is likely to be sailing nearby. And you've got a government credit card...

Well actually, it was an unlimited letter of credit from the president, one named Thomas Jefferson (maybe you've heard of him). The thing is, you are almost there, and a storm begins, the likes of which you haven't experienced before. Heavy rains, hurricane force winds, and it doesn't let up. You take shelter in the best spot you can find, but it is steep and rocky and wet. For six days the storm rages, and finally it's spent. You load the canoes as fast as you can, head the last few miles to the coast...and you've missed the trading ship.

And that's how Dismal Nitch got its name. The party of course was that of Lewis and Clark and their Corps of Discovery. The correct spelling is "niche", but they kept William Clark's version. He had many original spelling versions of a great many words in his journals.

From the top of the Astoria Bridge. Dismal Nitch is on the shoreline to the right, while Cape Disappointment would be on the left, just out of the picture. Photo by Mrs. Geotripper

Here's an example from the middle of their ordeal (from the Washington State Historical Society):

A Tremendious wind from the S. W. about 3 oClock this morning with Lightineng and hard claps of Thunder, and Hail which Continued untill 6 oClock a. m. when it became light for a Short time, then the heavens became Sudenly darkened by a black Cloud from the S. W. and rained with great violence untill 12 oClock, the waves tremendious brakeing with great fury against the rocks and trees on which we were encamped. our Situation is dangerous. we took the advantage of a low tide and moved our camp around a point to a Small wet bottom at the mouth of a Brook, which we had not observed when we Came to this cove; from it being verry thick and obscured by drift trees and thick bushes It would be distressing to See our Situation, all wet and Colde our bedding also wet, (and the robes of the party which Compose half the bedding is rotten and we are not in a Situation (not) to supply their places) in a wet bottom Scercely large enough to contain us, (with) our baggage half a mile from us and Canoes at the mercy of the waves, altho Secured as well as possible, Sunk with emence parcels of Stone to wate them down to prevent their dashing to pieces against the rocks; one got loose last night and was left on a rock a Short distance below, without rciving more dammage than a Split in her bottom— Fortunately for us our men are healthy. men Gibson Bratten & Willard attempted to go aroud the point below in our Indian Canoe, much Such a canoe as the Indians visited us in yesterday, they proceeded to the point from which they were oblige to return, the waves tossing them about at will I walked up the branch and giged 3 Salmon trout. the party killed 13 Salmon to day in a branch about 2 miles above, rain Continued.

Cape Disappointment Lighthouse from Waikiki Beach

I'm happy to say that our arrival at the peninsula on our vagabonding journey along the Cascadia Subduction Zone was a much more positive experience. For one, we didn't need a canoe to cross the Columbia River from Oregon. The four mile long Astoria Bridge worked out just fine. The weather was dry and calm. We had a reservation for a campsite in a pleasant forest on flat ground. And there was a pizza shop just down the road from the campsite.

The pizza shop had the audacity to close at like 8:00 pm, so we took our dinner out to Waikiki Beach on Cape Disappointment. It turns out that we were enjoying our evening repast on the very spot where the Lewis and Clark crew reached the Pacific Ocean on November 18, 1805, just a few days after leaving their "little dismal nitch". Strangely enough, Cape Disappointment was not named by Lewis and Clark. The cape already carried that moniker, although only for the previous 17 years. The Native Americans of the region knew the point as "Kah-eese".

The cape was first charted by the Spaniard Bruno Heceta as Cabo de San Rougue in 1775. He suspected a major river was present in the sandy shoals to the south, but his crew was more or less wiped out by scurvy, so he retreated south without further exploration. Twelve years later in 1788, a ship captained by John Meares sighted the cape, but couldn't confirm the presence of a major river, and so named the headland Cape Disappointment. The Columbia River was "discovered" and named in 1792 by an American captain, Robert Gray, and explored by a crew under the leadership of George Vancouver. When Lewis and Clark approached the Pacific Ocean in 1805, they had a reasonably accurate map of the lowermost 100 miles of the Columbia.

The North Jetty of the Columbia River. The forested area beyond the jetty was once open water.

The mouth of the Columbia has changed in many ways since the arrival of the Europeans and Americans. The shoals at the mouth of the river were deadly to ships, so two lighthouses were built on the cape in the 1800s, Cape Disappointment in 1856, and North Head in 1898. Nearly ten miles of jetties (rocky breakwaters lining the navigation channel) were constructed between 1885 and 1939. Sand started to accumulate on the north side of the jetty immediately, and within decades the entire coast was changed.

View south from North Head Lighthouse

The picture above is the scene from the North Head Lighthouse, and all the flatlands in the view are lands added since the jetty was constructed.

Beard's Hollow, a former water-filled cove

Beard's Hollow, just north of North Head Lighthouse, was once a cove along the coast, under water. Since construction of the jetty, a baymouth bar closed it off, and the cove filled with sediment. Within a few decades it has become a freshwater wetland with a growing forest.

Walking in Beard's Hollow

Cape Disappointment was an important landmark for sailing ships because it stood out so high along a relatively low-lying coastal zone. The cliffs are there because they are composed of basalt, which can be quite resistant to erosion. Given that the Cascades are a volcanic mountain range, it might seem to make sense that these are lava flows from the interior. Some lava flows from eastern Washington have reached the region, but these are probably not related. Part of the reason for thinking this way is a strange structure seen in close-ups.

Waves once crashed against the base of Cape Disappointment. The construction of the Columbia River jetties has caused the sand to back up and form wide beaches.

The pillow-sized lumps of basalt are called (surprise!) basalt pillows. This kind of shape occurs when basalt is erupted into water, such as at divergent boundaries on the ocean floor, or on seamounts. These rocks quite probably were scraped off the sinking slab of the Cascadia Subduction Zone and accreted to the edge of the continent. The subduction zone that has many people in the Pacific Northwest up in arms has been changing and altering the landscape for many millions of years.

The geologic map of the cape shows the basalts (Tc), and sand beaches (Qb) which have grown out since the construction of the jetties. Without the jetties, there would be no campground or pizza parlor at the park. Point of reference, though: if the big earthquake occurs, the sand flats will not be a very good place to be. The roads will probably severely disrupted by liquefaction, and the tsunami that will likely follow the earthquake will completely inundate the lowlands. It's a wonderful campground in good weather, but if you are there in an earthquake, don't hesitate. Drive for high ground, and if the roads are blocked, run for high ground.

Source: Northwest Geology Field Trips

The final note for this little exploration concerns the famous weather at the state park. Why are there not one, but two lighthouses? Cape Disappointment has been described as the foggiest place in the nation, with an average of 2,550 hours of fog every year: 106 days of poor visibility! Both times I've been there, I've spent afternoons and evenings in fine weather and woken up in the morning to rain. Just imagine! If you are there and the rain is pouring down, be sure to shelter in the Lewis and Clark Interpretive Center in the park. It's excellent.

We were looking forward to our next day. In all my travels, I've never been up the western side of the Olympic Peninsula, or into the Olympic Rainforest.

Northern Convergence: Mt. Revelstoke, Where the Columbia Mountains Reach to the Sky (and right into the clouds)

Thanks for all the attention to the post on exfoliation in Twain Harte! 4,000 hits and counting, it's been my most read blogpost in five years (about 10 or 15 times normal traffic). Today we are getting back to our tour of British Columbia and Alberta, one of the most beautiful regions in the world. We last looked at Craigellachie, the site of the completion of the Trans-Canada Railroad. As we continued down the highway, the mountains around us were becoming dramatic.

We had been traversing the Intermontane Belt, a region of high plateaus and relatively modest mountain ridges, and were now entering the Omineca Belt, a series of increasingly rugged mountain ranges, including the Purcell and Selkirk ranges, subdivisions of the Columbia Mountains. Yes, the Columbia, as in Columbia River. That's the Columbia in the picture below (actually a reservoir on the Columbia), a long distance upstream from the thread of water between Oregon and Washington in the Cascades. It is a huge watershed!

Our main goal for the day was to explore Mt. Revelstoke National Park, and the best way to do it on a tight schedule is to drive to the 1,938 meter (6,360 feet) summit. A beautiful 26 kilometer paved highway switchbacks up the flank of the mountain and ends at a parking lot just below the peak. From there one can walk a short trail to the summit area, or catch a van to the upper parking area. A network of short trails explores the alpine environment.

Storms had been wreaking gentle havoc with our trip for three days. We certainly didn't get the worst of the weather: a day before we arrived in Kamloops there had been intense thunderstorms and some areas of town were unexpectedly flooded. Drumheller, a town we would visit in a few days, was hit with a storm of golf-ball sized hailstones. Mostly we were rained on, and clouds obscured some of the views we had hoped to see (most notably at Mt. Garibaldi in the northernmost Cascades). We woke to sunshine in Kamloops, but as we drove east into the higher mountain ranges, the clouds seemed to be gathering on the higher peaks.

We reached the summit of Mount Revelstoke and had a look around. In a "cup half empty or half full" moment, the cloud deck lay just above us, so we had extensive views into the valleys below while the rugged high peaks above us were obscured. Even if partially hidden, the view was spectacular.

Mt. Revelstoke was the eighth national park in Canada, having been established in 1914. The park preserves a swath of alpine scenery from the shores of Lake Revelstoke on the Columbia River (around 500 meters, or 1,640 feet) to the summits of Revelstoke (1,938 meter, 6,360 feet) and Mt. Coursier (2,646 meters, 8,681 feet). The park encompasses four vegetation zones, an interior rain forest, subalpine Hemlock and Engelmann Spruce forest, subalpine meadows, and alpine tundra on the highest peaks. The region receives prodigious amounts of snow, and skiing was an early form of recreation on the mountain. One of the first ski jumps ever constructed was used in the park for years.

The park is not really notable for extensive rock outcrops in the most visited areas. In the very humid environment, vegetation and soils are widespread. The underlying rock is part of the Shuswap Metamorphic Complex, a series of Proterozoic and Paleozoic rocks that were deposited in the Pacific offshore of the North American Continent. The rocks were crushed into the edge of the continent in Mesozoic time, intruded here and there by Mesozoic granitic rocks, and exposed during mountain uplift in the early Cenozoic era. 

The growing season on Mt. Revelstoke is exceedingly short, essentially from late June to early September, but the plants are well adapted to bloom fast and die. The park is famous for the August wildflower display, although we were a bit early to see the best of it. There were some beautiful Glacier Lilies (no good pictures, but wait for my post on Glacier National Park), and some colorful Indian Paintbrush.

As always seems the case, the clouds were starting to lift, but our time was slipping away. We enjoyed several high peaks to the north clothed in wispy clouds, but we had to start down the mountain. And of course, the sun emerged!

From midway down the mountain we had a fine view across the valley to the Monashee Mountains, home to some of the oldest rocks in British Columbia, at around 2.2 billion years. The town of Revelstoke could be seen on the narrow plain below.

Glaciers cling to the high peaks, a kind of a preview of the spectacular icefields that we would be seeing in a few days in the Canadian Rockies. We intended to visit parts of Canada's Glacier National Park, but active wildfires had closed off access to most parts of the park.

About an hour later we pulled into the small town of Golden and checked into our hotel. The storm continued to break up, giving us a beautiful sunset over the Purcell Mountains.

Tomorrow would be the beginning of the climax of our trip, an exploration of Yoho and Banff National Parks in the Canadian Rockies.

Sand...Lots of Sand

Wrapping up my mini-exploration of the coast of Oregon leads me to the plainest of all subjects: sand. Or maybe not the plainest. We use the grains of sand on the beaches of the world as some sort of analogy for infinity, suggesting that the diminutive grains are so common as to be hardly worth our notice. Sand is so uniform that it served as a time keeper (remember Dorothy and the witch in the castle...). Boring?

A sand composed entirely of the gemstone peridot; the green-sand beach in Hawaii

I was convinced otherwise a long time ago. What does it take? For one, a handlens or a microscope. Even the plainest looking sand can turn into a pirate's treasure when viewed up close. Garnet, peridot, and other gemstones can often be seen among the quartz grains, and a single grain can tell a complex story of erosion and deposition, of burial and lithification (turning to stone), and liberation once again by erosion. There is even an excellent geo-blog based on sand.

On the other, there is the big picture. Sand covers large parts of some deserts (although not as much as folks tend to think). And sand is a major component of our shoreline systems.

Traveling along the rocky shoreline of Oregon, I wasn't thinking much about sand, but that changed when I saw how much sand influenced the topography along the coast. It starts with the rivers: Oregon has a lot of rivers, in stark contrast to most of California, my home state. The rivers provide copious amounts of sediment to the coastal systems. In the first picture above, at Del Rey Beach, we were traveling across the vast beach formed by sediments from the Columbia River. Wide and flat. Featureless. But what happens when the wind picks up? And you can trust that the wind blows quite freely on the Pacific Northwest coast.

Some of the sand gets picked up and blown inland. That is when things start to get interesting...

At Pistol River Beach, we can see how the sand piles up in dunes and moves inland. The dunes start altering the arrangement of rivers, deltas and estuaries. And then life gets involved, as grasses and shrubs start stabilizing the dune surfaces.

When the grasses and other pioneer species build up the organic content of the sand, trees can get a roothold, and forests start to grow. At times the active sections of the dunes can shift and forests get buried. There are a lot of complex interactions going on in this environment.

I have often thought of lakes as being the result of either glaciers, landslides, or human dam-building (and the occasional volcanic crater filling). I hadn't given much thought to the possibility of lakes forming around dunes, primarily because I spend most of my time in deserts where there isn't enough water. But there are lots of lakes in the dune fields of Oregon, especially around Florence and the Oregon Dunes. Many of the lakes are fed by groundwater, while others are connected by rivers and streams.

I didn't take many shots of any of the big lakes on this trip, but you can see from these shots at Sutton Creek how dunes can conceivably form dams.

A fascinating region! I think I'll be back...

A Convergence of Wonders: Day 4, Cape Disappointment and Real Disappointments

I've been a desert rat for a long time, and I have managed most times to visit the Pacific Northwest during unusual climatic regimes, i.e. sunny weather. I spent four days in Seattle once when temperatures hit close to 100 degrees, and I've flown up the spine of the Cascades when not a single cloud could be seen on the horizon. Add to this that summer is when it doesn't rain on my field trips.

I really shouldn't be disappointed that it chose to rain on us on the fourth day of our trip this year. Really, it could have been far worse; it could have rained every day. But, why on St. Helens day? Oh well, it was certainly an interesting day, and if one is going to visit a temperate rainforest, one might as well do it on a temperate rainy day.

Museums and visitor centers are supposed to open at 8:00 AM, but not the one we wanted to see. We had two hours to explore a bit. We set out to hike through the forest to the North Head Lighthouse and have a look around.

It was rainy and green. Mrs. Geotripper snapped a shot of Geotripper getting soaked at the overlook. It was my wettest moment of the trip.

The mouth of the Columbia has been a treacherous region of shifting sand shoals and unpredictable currents. Hundreds of ships have found destruction here. The lighthouses at Cape Disappointment were constructed in the late 1800s to do the thing they do, warning ships of the danger.

I noted the wide beaches of the Cape in the previous post. We could make out the wide expanse of sand from the top of the cliff at the lighthouse. The existence of these beaches here is also related the danger to ships.

To make the currents at the mouth of the Columbia River more predictable, jetties were constructed between 1885 to 1917 to direct the flow of the river. They extend several miles into the Pacific (only part of the north jetty is visible in the picture below). Because they block wave action, sand moving down the coast backs up against the outside of the jetty forming the wide beaches up coast. The jetties have been weakened by a century of storms and are in danger of being breached causing serious problems for ship traffic moving up and down the river.  Many millions of dollars are being spent to shore them up.

The Lewis and Clark Interpretive Center is a marvelous introduction to the 1804-06 exploration of the Pacific Northwest (and not to be mercenary about it, but it was dry inside, too!). The staff generously provided a meeting room for some of our students to do their presentations. After several hours we hit the road to Mt. St. Helens, hoping against hope that a supposed 60% chance of showers would translate into a few momentary views of the volcano.

No dice...that's the view below that we had from the Johnston Ridge Observatory at the end of Highway 504. There was no break in the storm. We checked out the very fine visitor center and watched the video, but it wasn't quite the same thing as seeing the volcano itself.

There were certainly a few close up details to enjoy; I had never seen the trilliums blooming before.

Coldwater Lake provided an idea of the power of the volcano...it didn't exist prior to the 1980 eruption. The incredible debris avalanche and ashflow blocked the flow out of Coldwater Canyon, forming a lake several miles long. We could also see the vast area of destruction in the Toutle River Valley, and the regrowth of the forest on the slopes below the volcanic cone. There are places we need to return to...

Of course, the moment we crossed the summit of the Cascades, the rain shadow effect took over, and the clouds were scattering and breaking up. By the time we arrived at our camp in Yakima, conditions were dry. That's the way it is sometimes...

My northwest associates can probably confirm this, but I think this is an outcrop of Cretaceous metasedimentary rocks near Rimrock Reservoir upstream of Yakima.