Atlas · Today in history · volcanic
May 18 MCMLXXX 1980
Mount St. Helens eruption
Washington State — death toll estimated at 57.
At 8:32 a.m. PDT on May 18, 1980, a M5.1 earthquake triggered the largest landslide in recorded history on Mount St. Helens's north flank. The debris avalanche unroofed the volcano's cryptodome, producing a lateral blast that flattened 230 square miles of forest at speeds up to 680 mph. 57 people died. The Pyroclastic flows that followed reshaped the mountain's summit; the eruption column reached 80,000 feet and deposited ash across eleven U.S. states.