Today in history- Mount St. Helens erupts.


Some fascinating facts regarding the Mount St. Helens eruption:

1975—U.S. Geological Survey geologists forecast that Mount St. Helens would erupt again, “possibly before the end of the century.”

March 20, 1980—A magnitude 4.2 earthquake signaled the volcano’s reawakening after 123 years.


Spring 1980—Rising magma pushed the volcano’s north flank outward 5 feet per day.


Morning of May 18, 1980— The largest terrestrial landslide in recorded history reduced the summit by 1,300 feet and triggered a lateral blast. Within 3 minutes, the lateral blast, traveling at more than 300 miles per hour, blew down and scorched 230 square miles of forest. Within 15 minutes, a vertical plume of volcanic ash rose to over 80,000 feet.


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.

The volcanic ash cloud drifted east across the United States in 3 days and encircled Earth in 15 days.

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.

The May 18, 1980, eruption was the most economically destructive volcanic event in U.S. history.

Small plants and trees beneath winter snow, and roots protected by soil, survived the May 18, 1980, eruption and now thrive. Thousands of birds, mammals, reptiles, amphibians, and millions of hatchery fingerlings perished in the eruption. Wind-dispersed spiders and scavenging beetles were among the first animals to return to Mount St. Helens.


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.

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.

October 1980 to 1986— Over the course of 17 episodes, lava eruptions filled the crater, building a lava dome that reached 876 feet above the crater floor. Since 1986, snow and rock have accumulated in the deep, shaded crater and formed Crater Glacier, the youngest glacier on Earth.

September 2004—Mount St. Helens reawakened, and it erupted continuously until January 2008.

Today you can visit Mount St. Helens, a few hours’ drive from my home. What do you think? Would you want to see it?

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2 responses to “Today in history- Mount St. Helens erupts.”

  1. Did you know that on May 18, 1980 you were on your way to Washington? I have a picture from that day.

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