Definitions for "1980 eruption of Mount St. Helens"
The 1980 eruption of Mount St. Helens (VEI = 5, 1.2 km3 of material erupted) was a major catastrophic volcanic eruption in the 20th century. The eruption was the most significant to occur in the lower 48 U.S. states in recorded history, exceeding the destructive power and volume of material released by the 1915 eruption of California's Lassen Peak.