Mount St. Helens, an active stratovolcano, has an elevation of 8,363 feet. It is located in Skamania County, Wash., in the Pacific Northwest region of the United States.
From March 16 to May 17, 1980, Mount St. Helens experienced a series of small earthquakes, which culminated in a catastrophic eruption on May 18. At the time, it was the deadliest and most economically destructive volcanic event in the history of the United States.
The eruption impacted the size of the mountain, creating a crater 1.2 miles across east to west, 1.8 miles across north to south, and 2,084 feet deep. Prior to the eruption, it stood at 9,677 feet in elevation; it lost 1,314 feet in the eruption. The mountain lost a volume of 0.67 cubic miles.