Mount St. Helens is most notorious for its catastrophic eruption on May 18, 1980, at 8:32 a.m. PDT,[2] the deadliest and most economically destructive volcanic event in the history of the United States. Fifty-seven people were killed; 250 homes, 47 bridges, 15 miles (24 km) of railways, and 185 miles (298 km) of highway were destroyed.