Mount St. Helens
From the Portland, OR area we had a short 1½ hour drive north to Castle Rock, WA, where we stopped at Mount St. Helens RV Park. Mount St. Helens RV has paved roads, gravel pads, full hookups with 30 amp electric, cable TV (limited channels), and free Wi-Fi. Unfortunately, the sites are quite narrow and short, so we had to park our car in an empty site across the road. The campground accepts Passport America for a 50% discount for one night of your stay, so it's not bad for a one or two night stay to visit Mount St. Helens. The photo below shows our site at Mount St. Helens RV.
Mount St. Helens RV Park is located only a few miles from the Mount St. Helens Visitor Center and about 40 miles from Johnston Ridge Observatory overlooking Mount St. Helens itself. Mount St. Helens, which is yet another volcano in the Cascade Range, is famous for the catastrophic eruption that took place in 1980.
Much of the area around Mount St. Helens was part of Gifford Pinchot National Forest. The mountain and the area devastated by the 1980 eruption to the north was designated Mount St. Helens National Volcanic Monument in 1982.
It was a short drive from Portland, so we arrived in Castle Rock early. After we got set up, we decided to drive to the Mount St. Helens visitor center a few miles up the road at Silver Lake. Actually, we found out later there are several visitor centers for Mount St. Helens. The visitor center closest to the campground is outside the national monument and national forest and is operated by the state of Washington. There is also the Hoffstadt Visitor Center about halfway to Mount St. Helens (also outside the national monument and forest boundaries) operated by Cowlitz County. Then there is the Forest Learning Center operated by Weyerhaeuser Lumber a little farther down the road from the Hoffstadt Visitor Center (also outside the national monument and forest). Finally, there is a visitor center inside the national monument at the end of Spirit Lake Highway at the Johnston Ridge Observatory. The Johnston Ridge Observatory is operated by the U. S. Forest Service.
The state-operated visitor center has some nice displays and an excellent movie. Although similar information is presented at the Johnston Ridge Observatory at the end of Spirit Lake Highway, there was an advantage in learning more about Mount St. Helens and the 1980 eruption before we drove into the park. As we came to various features along the road, we had a better understanding of what they were and how they fit into the sequence of events that occurred during and after the eruption.
Other than the movie, probably the most helpful feature at the state visitor center was a scale model of the area surrounding Mount St. Helens. There is a similar, larger model at Johnston Ridge, but, as we said, seeing this one before driving the road all the way to Johnston Ridge was helpful. The model is shown in the photo below.
the eruption, Mount St. Helens was the fourth highest mountain in the
Cascades and was known for its beautiful symmetry. All that changed on May 18, 1980.
Prior to 1980, the most recent period of volcanic activity at Mount St. Helens was back in the 1840s and 1850s. Around the middle of March, 1980, there were several minor tremors centered around Mount St. Helens indicating magma might be moving underground. Then on the afternoon of March 18, 1980, there was a shallow, magnitude 4.2 earthquake indicating the volcano was definitely coming back to life.
Scientists flocked to the site and set up monitoring instruments. Over the next several days, there was a swarm of minor earthquakes. There was a minor volcanic eruption on March 27 that formed a new crater and sent an ash column 7,000 feet into the air.
The tremors continued and in early April, scientists reported a large bulge on the mountain's north face. The bulge grew and the tremors and minor eruptions continued until the morning of May 18, 1980. At 8:32 AM, two months to the day after the initial earthquake, there was a magnitude 5.1 earthquake centered directly under the north side of the mountain. The second earthquake triggered a huge landslide on the north slope of the mountain, which in turn, exposed the magma in the neck of the volcano causing it and trapped steam to explode. An ash cloud eventually reached 12 miles into the air and ended up circling the globe.
The landslide and the subsequent near-supersonic blast of hot gasses and debris from the eruption caused devastation as much as 19 miles from the volcano. The heat from the blast melted the mountain's glaciers and snow cover creating massive mudslides. The mudslides carried with them rocks and boulders. These cement-like slurrys are called lahars. Trees were blown over like matchsticks. In aerial photos taken after the eruption, the forests looked like freshly-mown hay fields with the tree trunks all aligned and pointing back toward the volcano. Enough timber to build 100,000 houses was destroyed or damaged.
Spirit Lake Highway that we drove into the park is a new road that wasn't opened until the 1990s. The
mudslides and lahars that flowed down the North Fork of the Toutle
River destroyed much of old State Highway 504. The new road travels a safe distance from the river farther up the hillside. The
next photo is
looking up the North Fork of the Toutle River toward Mount St. Helens.
The tan-colored straight line near the center of the photo is the
remnant of the old road.
The next photo is a different area that gives a little better idea of how the debris spread out in the valley. The gray area is debris from the mudslides, and the light-colored spots near the center of the gray areas are the river.
In an area along a smaller stream, we saw trees half buried in the ash and debris along the banks.
We stopped at the Weyerhaeuser Forest Learning Center, but, unfortunately, it is only open Fridays, Saturdays, and Sundays (we were there on a Tuesday). Weyerhaeuser is a major property owner on the western side of the national forest, and they lost 68,000 acres of timber equal to 12 million board feet of lumber. They also lost logging camps, roads and bridges, railroad track and rail cars, and many pieces of logging equipment in the eruption. Although no replanting was done inside the national forest, Weyerhaeuser quickly salvaged what lumber they could from their property and began cleanup. They replanted millions of trees. This helped re-establish wildlife habitat and stabilize the soil to reduce runoff from carrying silt and ash to nearby streams and rivers. This sculpture of a forester planting trees outside the learning center commemorates Weyerhaeuser's replanting efforts.
Weyerhaeuser replanted one large area with nobil fir trees. Nobil firs grow with a distinctive horizontal pattern to the branches, at least at the age of the trees were on these hillsides. You can see the horizontal pattern in the photo below. It kind of made our eyes feel blurry when looking at entire hillsides planted with these trees.
A little farther along Spirit Lake Highway is Castle Lake Viewpoint. Castle Lake (at the lower right of the photo below) near the base of Mount St. Helens was created when landslide debris dammed up one of the tributaries of the Toutle River. When we stopped for this photo, we were happy to see the clouds that were previously obscuring the top of Mount St. Helens were finally starting to dissipate.
Debris from the eruption also dammed up Coldwater Creek to form another new lake called Coldwater Lake. Unlike Castle Lake that can only be reached by hiking, Coldwater Lake is easily accessible by car, and it even has a boat launch (non-powered boats or electric motors only). The next photo shows Coldwater Lake.
At the end of Spirit Lake Memorial Highway is Johnston Ridge Observatory. The observatory is located about 5 miles away from the north slope of the volcano. The ridge on which the observatory is located is named for David Johnston, who was U. S. Geological Survey volcanologist who was on duty monitoring geological activity on May 18, 1980. David Johnston was one of 57 people who lost their lives the day of the eruption.
The observatory is designed to be unobtrusive in the stark, blast-zone terrain. The building is low, it is built into the ridge behind it, and it even has non-reflective glass to help it blend into the surroundings. The photo below shows the Johnston Ridge Observatory from the hill above it.
Inside, there are displays about the 1980 eruption. There are photos and written accounts by a number of people who were nearby the day of the eruption, but survived. There is also a theater with another excellent movie about the volcano and the events leading up to the 1980 eruption.
A demonstration that was fun has a platform on the floor that you can jump on to watch the vibrations register on a seismograph. The next photo shows Paul seeing how big an earthquake he can make.
Outside the observatory there are walkways and overlooks that provide excellent views across the area of the greatest devastation right into the crater of Mount St. Helens.
The next photo is a closer shot of the crater and the lava dome that formed after the eruption. The lava dome, which is a build-up of thick, pasty lava, is currently about 1,100 or 1,200 feet high. The dome continues to grow slowly, and at its current growth rate, it would take over 200 years to build Mount St. Helens back up to its pre-1980 height, which was 1,300 feet higher. Although smoke is sometimes seen from the crater, as far as we could tell those are clouds in the photo below.
Spirit Lake, shown in the next photo, is located near the base of the volcano to the left.
Before the eruption, Spirit Lake was surrounded by lush forests and was a popular tourist destination. Some of the rock and debris from the initial landslide ended up in Spirit Lake. So much rock hit the lake with so much force that the water in the lake was sloshed several hundred feet up the sides of the surrounding slopes. When the water ran back into the lake, it carried with it downed trees. The landslide also raised the surface of the lake by about 200 feet, but it also raised the bottom of the lake by 295 feet resulting in a higher, but shallower lake.
The immediate area to the north of the mountain still looks rather barren 29 years after the eruption. The Indian paintbrush (red) and Cardwell penstemon (purple) in the photo below were growing on the somewhat protected side of Johnston Ridge facing away from the volcano.
There were wildflowers on the top of the ridge as well, but they were a little more sparse. You can see some of them in the earlier photo of the outside of the observatory building.
After exploring the area around Johnston Ridge Observatory, we headed back to the RV park. We had seen other volcanoes or the results of volcanic activity throughout our travels around the country, but to see the devastation that occurred from a volcanic eruption that occurred during our lifetime was very moving.
We left the Mount St. Helens area the next morning and continued north.