The Mount St. Helens' eruption in Washington on May 18, 1980 is the worst volcanic eruption in U.S. history, killing 57 people and spewing 520 million tons of ash across the U.S.
The Mount St. Helens' eruption in Washington on May 18, 1980 is the worst volcanic eruption in U.S. history, killing 57 people and spewing 520 million tons of ash across the U.S.