When Mount St. Helens erupted 45 years ago on May 18, 1980, the event devastated more than 150 square miles of forest and recreation area, killing 57 people and countless animals. The eruption lasted nine hours and spewed ash and debris more than 15 miles into the air. The ash spread across the United States in three days, with detectible amounts covering 22,000 square miles. About 7,000 deer, elk and bears perished, as well as all birds and most small mammals. Some burrowing animals managed to survive – they were below ground level or water surface.
The velocity of the blast was 300 miles per hour, blowing down 4 billion board feet of timber. That’s enough to build 150,000 homes.
Mount St. Helens is the youngest of the five volcanoes in Washington. A composite volcano, it tends to erupt explosively with considerable danger to nearby life and property. The most recent eruptive periods began about AD 1800.
The first documented observation was in 1792 by British Royal navy officer Captain George Vancouver who was charting the inlets of Puget Sound. Several months later, he named the mountain in honor of his fellow countryman who held the title Baron St. Helens, the British ambassador to Spain. Vancouver also named Mounts Baker, Hood and Rainier for British naval officers. Other reported eruptions were in 1831, 1835 and 1842. Another eruption may have occurred in 1854.
Local Native Americans and early settlers in the region witnessed occasional violent outbursts of Mount St. Helens. The Native Americans called the mountain Lawetlat’la or “smoker.”
Studies have shown Mount St. Helens has experienced approximately ten main eruptive periods from 1800 to 1980. It must be remembered that the volcano shows continued activity and is not dormant. Future eruptions are possible.