The 1980 eruption of Mount St. Helens

Noticeable volcanic activity began on 20 March 1980 with a series of tremors centred just beneath the north flank. At 8:32 a.m. PDT on 18 May the bulging north flank slid away in a landslide and the volcano erupted, killing 57 people and devastating some 210 square miles of wilderness. The cone was blasted away and replaced by a horseshoe-shaped crater, with the mountain losing 1,700 feet from a pre-eruption height of 9,680 feet. Damage was put at over one billion dollars in 1980 terms.

Eruption start

1980-03-27

Eruption end

1986-10

Volcanic Explosivity Index (VEI)

5

Volcano

St. Helens

GVP volcano page

volcano.si.edu/volcano.cfm?vn=321050

Category: Disasters & Incidents

Tags: washington, cascades, lateral blast, landslide

Coordinates: 46.2, -122.18

Part of Volcanic eruptions of VEI 5 and above since 1900

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