Mount St. Helens
St. Helens, Mount, an active volcano in the southwestern part of Washington state. It is in the Cascade Range just west of Mount Adams and between Mount Rainier and Mount Hood. It erupted with a violent explosion on May 18, 1980, causing widespread destruction and the loss of 57 lives. The eruption reduced the height of the volcano from 9,677 feet (2,950 m) to 8,364 feet (2,549 m) and removed a major part of the north slope. Minor eruptions have occurred since the violent 1980 eruption. Mount St. Helens's most recent previous period of activity began in 1831 and continued for 25 years.
