It was an early Spring morning and I was outside washing my car when I heard the noise. A booming sound that came out of the North and rumbled down the valley to my driveway in Eugene, Oregon. I knew it was big. I just didn't know how big until later that day.
This was back in 1980 and the booming sound I heard was a volcanic explosion. I'm talking about Mount St. Helens. The once dormant volcano in Washington State had roared back to life in a ferocious blast that can only be described as epic.
The eruption wasn't a total surprise. There were some warning signs. For about two months prior there were several ominous indications that something was amiss. A couple of large earthquakes and over ten thousand small earthquakes were recorded in the mountains vicinity, several steam venting episodes also took place, a massive bulge of over 450 feet could be easily seen protruding from the North side of the mountain, and finally, on the morning of May 18, 1980, the pressure was more than she could handle. A massive lateral blast of such magnitude literally reduced the height of the mountain by a quarter mile.
A landslide of major proportions slid down the North side of the mountain taking snow, ice and several glaciers, now melted by the terrific heat of the blast sloughed off the side of the mountain causing a massive volcanic mudslide that flooded two rivers and carried debris downstream for over 50 miles.
The blast and resulting landslide quickly depressurized the volcano's magma system causing several more powerful explosions. A 600 degree gas and steam blast flew down the side of the mountain at over 300 miles an hour laying the forest landscape in front of it stripped bare and flat destroying everything in its path.
The event killed 57 people, destroyed close to 250 homes, 47 bridges, 15 miles of railroad tracks and 185 miles of highway. The lateral blast flattened 230 square miles of forest land and released an estimated 24 megatons of thermal energy. It left a crater over a mile wide.
The blast could be heard for over 150 miles in all directions.
This was the most catastrophic volcanic eruption in the history of the United States.
Mount St. Helens, located in Southern Washington State, is part of the Cascade Volcanic Arc. This arc runs through three western states. California, Oregon, and Washington and continues into British Columbia. It's comprised of over twenty major volcanoes. Most are dormant but as we've seen with Mount St. Helens, any one of them can become active at any time.
The devastated area has been preserved in the Mount St. Helens National Volcanic Monument. It was created to preserve the volcano and allow its aftermath to be scientifically studied.
If you should ever want to see this volcano for yourself, The Washington State park service operates a visitor center at silver lake. A mile-long hiking trail along the shores of Silver Lake will lead you to a picture-perfect view of the mountain.