Mt. St. Helens
Eruption: May 18, 1980

At 8:32 a.m. Sunday morning, May 18, 1980, Mt. St. Helens erupted.

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34th Anniversary


Shaken by an earthquake measuring 5.1 on the Richter scale, the north face of this tall symmetrical mountain collapsed in a massive rock debris avalanche. Nearly 230 square miles of forest was blown over or left dead and standing. At the same time a mushroom-shaped column of ash rose thousands of feet skyward and drifted downwind, turning day into night as dark, gray ash fell over eastern Washington and beyond.

The eruption lasted 9 hours, but Mount St. Helens and the surrounding landscape were dramatically changed within moments.

In 1982 the President and Congress created the 110,000-acre National Volcanic Monument for research, recreation, and education. Inside the Monument, the environment is left to respond naturally to the disturbance.