Eruption History

The most famous eruption of Mt. St. Helens, took place on May 18, 1980 at 8:32 am (PDT). Triggered by a 5.1 magnitude earthquake with an epicenter directly below the volcano, Mt. St. Helens erupted. This eruption soon became the most studied eruption of the twentieth century. In the 1980 eruption, almost 10 million trees were flattened to the ground like toothpicks and carried to Spirit Lake, almost completely covering its surface. The eruption went on for nine hours, the famous 1980 eruption was categorized as a VEI 5. The picture below was taken by Donald A. Swanson during the May 18,1980 eruption.