I visited Mount St. Helens last week. I’ve been there twice before, both times after the eruption and both times to climb its south face to the crater rim.
On May 18, 1980 I was racing at a motocross event in McMinnville, Oregon. I can’t remember if anything was announced at the race, but I vividly remembering leaving the race track and turning onto the highway heading north and immediately seeing a huge plume of smoke and ash where Mount St. Helens used to be. Talk about a car full of people with dropped jaws!
Before the May 18, 1980 eruption Mount St. Helens was a very pretty, symmetrical mountain. It is hard for me to believe that it erupted last in the 1840 or 1850′s. I had no idea mountains rebuilt themselves that fast. Native Americans said the mountain frequently erupted. In March of 1980 a crevasse formed on the north side of the mountain and started venting steam. The crevasse widened and the venting of plumes of steam and ash increased. Geologists were certain that we were in for a major volcanic eruption soon. In fact geologist David Johnston called it pretty much 100% in his prediction that a major eruption would occur in the next few months and it would blow out the north side of the mountain. There would be pyroclastic gas flows that would annihilate every living thing for several miles and there would be flooding of the Toutle River due to melted glacial snow. David Johnston was eight miles from the blast on May 18th and only lived to witness the eruption up to the pyroclastic flows. He was buried in the collapsing mountainside and his body was never found.
The image above is from the northeast and shows the north side of the volcano and the blast zone of mud and debris 34 years later.
A closer image shows the two lava domes growing inside the crater. Climbers come up the south (opposite) side and only scientists get to go into the crater.
At the base of the north side of the mountain was Spirit Lake, a popular recreation and summer camp area. The owner of the Mt. St. Helens Lodge was an eight-something year old named Harry Truman (not the president). Harry was told the mountain was going to erupt soon and what would happen when it did. He wouldn’t leave. In the 1980′s I thought he was crazy. Now that I’m older I can better understand why he stayed. He had lived there since at least the 1930′s. He had no place else to go. He would not have had a very happy life if he had left. Harry is now buried in 120 feet of mud under 30 feet of water.
They say the pyroclastic flows started at 220 miles per hour and somehow accelerated to 670 miles per hour. They may have broken the sound barrier. Most of the 57 people who died that day were asphyxiated by gas and ash. There was also flying debris, falling trees, and, if you were close enough to the volcano, 360 degree heat.
Everything within 8 miles of the eruption was vaporized to dust. The explosion was 1600 times more powerful than the Hiroshima bomb blast. Spirit Lake and Toutle River waters were flashed to steam, causing a second explosion that was heard north of the mountain for hundreds of miles.
Trees were flattened in a 19 mile radius. Trees beyond 19 miles were killed, but still standing. 150 elk, 5000 deer, and 12 million salmon fingerlings were killed.
A twelve foot wall of water (basically a twelve foot wall of logs) came down the Toutle River, taking out bridges and houses along the way. I-5 was shut down until the flood passed. I hadn’t thought about it before, but when you suddenly heat a mountain glacier to 360 degrees, you get a lot of melt water.
People were warned not to be on the mountain that day. People being people, they were. One of those killed was a National Geographic photographer. His car was found, he was not. I suspect a disproportionate number of the other people that were up there that day were probably photographers, too. I mean, really, a glaciated mountain spewing plumes of steam and ash? Who wouldn’t want an image of that? Some of the survivors told harrowing tales of racing to their cars and speeding down the mountain roads just seconds ahead of the dust cloud.
After the eruption Spirit Lake started re-forming again, 120 feet higher in elevation. It had no outlet so there was concern about it breaching a mud wall and causing flooding downstream. At first it was pumped to keep the water level stable, then a long tunnel was drilled through a ridge to provide it with an outlet in the proper direction.
Everybody was stunned at how fast nature began to recover. Insects and animals that lived underground survived. Bushes sprouted. Forestry crews and volunteers replanted forests. Those trees are a healthy thirty years old now.
We have found many ways to manipulate and control nature, but events like volcanic eruptions, especially of a mountain close to home, remind us of the awesome power that is out there. And the even more awesome ability nature has to heal itself.