On May 18, 1980, a major volcanic eruption occurred from Mount St. Helens, a volcano in Washington, in the United States. The eruption was recorded as a 5 on the Volcanic Explosivity Index. Throughout the two months before the eruption, there was a series of earthquakes and steam was vented from the mouth of the volcano. A total of 57 people died in the eruption. Including Harry R. Truman, who ran Spirit Lake, and volcano expert David A. Johnston.