Mount Saint Helens is a volcano in the Cascade Mountains, 95 miles (153 kilometers) south of Seattle. Mount St. Helens erupted violently on May 18, 1980. The eruption resulted in 57 deaths. It also caused hundreds of millions of dollars of damage to the surrounding area. Volcanic explosions blasted away more than 1,000 feet (300 meters) from the peak and created a huge crater. The volcano’s elevation after the 1980 eruption was 8,364 feet (2,549 meters) above sea level. The eruption of Mount St. Helens was the first to occur in the continental United States outside Alaska since 1917, when Lassen Peak in northern California last erupted.
Mount St. Helens has erupted many times in the past 4,500 years. It was inactive from 1857 until 1980. Hot ash and rocks from the 1980 eruption started forest fires and melted snow on the upper slopes of the mountain. The resulting floods and mud slides washed away buildings, roads, and bridges. Explosions flattened millions of trees. The eruption also spread a thick layer of volcanic ash over a wide area. The ash destroyed crops and wildlife and blanketed cities. Small eruptions occurred between May 1980 and 1986. A series of small eruptions also began in 2004. None of these eruptions has resulted in deaths or major property damage. Geologists expect Mount St. Helens to continue to erupt from time to time.
