Dame tu opinion At 8:32 a.m. PDT on May 18, 1980, Mount St. Helens, a volcanic peak in southwestern Washington, suffered a massive eruption, killing 57 people and devastating some 210 square miles of wilderness.Mount St. Helens is located in the Cascade Range and stood 9,680 feet before its eruption. The volcano has erupted periodically during the last 4,500 years, and the last active period was between 1831 and 1857. On March 20, 1980, noticeable volcanic activity began with a series of eart...