At one time scientists referred to volcanoes that had not erupted in a long time as "extinct." They were proved wrong when Washington state's Mount St. Helens, which had been dormant since 1857, became active in late March, 1980. It began to bulge noticeably in mid-April, and at 8:32 A.M. on May 18, belched out a hot (660 degrees Fahrenheit) cloud of gas and ash that destroyed every living thing within a two hundred mile radius, including entire coniferous forests, tens of thousands of animals, and fifty-seven people. The direct cause of the disaster was a 5.1 magnitude earthquake about a mile beneath the surface. The resulting landslide (including "lahars," mudslides from melted snow), the largest in U.S. history, broke open the peak, allowing the gas and ash to escape and shortening the mountain by 1,313 feet. The eruption lasted nine hours. Particles of ash reached the east coast in three days and within fifteen days had circled the globe. Today Mount St. Helens and the surrounding area have been set aside as a National Volcanic Monument for both recreation and research.