30 Cool Facts about Mount St. Helens

General Information Product 103

In cooperation with the U.S. Forest Service and Mount St. Helens Institute
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Commemorating the 30th anniversary of the 1980 eruptions of Mount St. Helens 1-During the past 4,000 years, Mount St. Helens has erupted more frequently than any other volcano in the Cascade Range. 2-Most of Mount St. Helens is younger than 3,000 years old (younger than the pyramids of Egypt). 3-Some Native American names that refer to smoke at the volcano include- Lawala Clough, Low-We- Lat-Klah, Low-We-Not- Thlat, Loowit, Loo-wit, Loo-wit Lat-kla, and Louwala-Clough. 4-3,600 years ago-Native Americans abandoned hunting grounds devastated by an enormous eruption four times larger than the May 18, 1980 eruption. 5-1792-Captain George Vancouver named the volcano for Britain's ambassador to Spain, Alleyne Fitzherbert, also known as Baron St. Helens. 6-1975-U.S. Geological Survey geologists forecasted that Mount St. Helens would erupt again, 'possibly before the end of the century.' 7-March 20, 1980-A magnitude 4.2 earthquake signaled the reawakening of the volcano after 123 years. 8-Spring 1980-Rising magma pushed the volcano's north flank outward 5 feet per day. 9-Morning of May 18, 1980- The largest terrestrial landslide in recorded history reduced the summit by 1,300 feet and triggered a lateral blast. 10-Within 3 minutes, the lateral blast, traveling at more than 300 miles per hour, blew down and scorched 230 square miles of forest. 11-Within 15 minutes, a vertical plume of volcanic ash rose over 80,000 feet. 12-Afternoon of May 18, 1980-The dense ash cloud turned daylight into darkness in eastern Washington, causing streetlights to turn on in Yakima and Ritzville. 13-The volcanic ash cloud drifted east across the United States in 3 days and encircled Earth in 15 days. 14-Lahars (volcanic mudflows) filled rivers with rocks, sand, and mud, damaging 27 bridges and 200 homes and forcing 31 ships to remain in ports upstream. 15-The May 18, 1980 eruption was the most economically destructive volcanic event in U.S. history. 16-Small plants and trees beneath winter snow, and roots protected by soil, survived the May 18, 1980 eruption and now thrive. 17-Thousands of birds, mammals, reptiles, amphibians, and millions of hatchery fingerlings perished in the eruption. 18-Late May 1980-Wind-dispersed spiders and scavenging beetles were among the first animals to return to the Mount St. Helens area. 19-The landscape devastated by the eruption has evolved into a rich and diverse habitat for plants and animals. 20-Effects of the May 18, 1980 eruption continue today. Biologists help wild salmon and steelhead by giving them a tank-truck ride to the pristine, clear creeks above sediment-choked rivers. 21-Late spring through fall 1980-Explosive eruptions on May 25, June 12, July 22, August 7, and October 16-18 rocked Mount St. Helens and sent ash to distant communities. 22-1982-Mount St. Helens National Volcanic Monument was established for all to observe both the awesome destruction and the remarkable recovery of plants and animals. 23-October 1980 to 1986- Over the course of 17 episodes, lava eruptions began filling the crater, building a lava dome that reached 876 feet above the crater floor. 24-Since 1986, snow and rock accumulating in the deep, shaded crater formed Crater Glacier, the youngest glacier on Earth. 25-September 2004-Mount St. Helens reawakened, and it erupted continuously until January 2008. 26-October 2004 to January 2008-Growing lava domes displaced and then divided Crater Glacier into east and west lobes. The ice lobes moved downslope as fast as 6 feet per day, converging below the lava dome a little more than three years later. 27-During the 2004 to 2008 eruptions-Mount St. Helens settled one half inch due to magma withdrawal beneath the volcano. 28-The Global Positioning System (GPS) instrument that detected the settling of Mount St. Helens can detect movement of as little as 1/16 of an inch and uses less power than a refrigerator lightbulb. 29-During the 1980 to 1

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30 Cool Facts about Mount St. Helens
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U.S. Geological Survey
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Volcano Science Center
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