On May 18, 1980, a major volcanic eruption occurred at the Mount St. Helens volcano in Washington state. The eruption was the largest eruption in the continental United States in the last 100 years and is often declared the most disastrous volcanic eruption in US history.
The eruption caused the entire north face of the volcano to slide away, creating the largest landslide ever recorded. This landslide allowed the partially liquefied rock to explode out northwards.
The eruption column shot 80,000 feet into the atmosphere and ash was spread over 11 states. Snow, ice, and entire glaciers melted, forming mudslides that traveled for 50 miles. The thermal energy released during the eruption was equal to 26 megatons. For comparison, the atomic bomb dropped on Hiroshima was 15 kilotons (0.015 megatons). The Mount St. Helens explosion was equivalent to 1,600 times the size of the atomic bomb dropped on Hiroshima
57 people were killed in the explosion. The explosion caused $3.03 billion in damage.