Today in the 20th Century: The Most Disastrous Volcanic Eruption in U.S. History - Mount St. Helens, May 18,1980

The tremors began on March 16, 1980. Eleven days later, a first explosion resulted in a 250-foot wide crater on the top of the mountain. Mount St. Helen had awakened and shook the area in warning. Not everyone was listening. Despite the tremors and the initial blast, despite the warnings issued by the authorities, despite the National Guard's roadblocks, many residents still refused to evacuate the area.

Aerial picture of Mt St Helen's eruption on May 18, 1980, taken by Richard Gordon Bowen

On May 18, 1980, a massive 5.1 magnitude earthquake triggered the most disastrous volcanic eruption in United States history. The high-pressure explosion ripped off the north face of the mountain causing the largest landslide ever recorded while volcanic ash blasted in the air and eventually landed in 11 different states. The eruption and avalanche destroyed the area and killed 57 people.

Aerial picture of Mt St Helen's eruption on May 18, 1980, taken by Richard Gordon Bowen

Aerial picture of Mt St Helen's eruption on May 18, 1980, taken by Richard Gordon Bowen

Ash clouds from Mount St. Helen, taken by Richard Gordon Bowen
Aerial picture of the crater left at the summit of Mt. St. Helens, taken by Richard Gordon Bowen

Ash clouds from Mount St. Helen, taken by Richard Gordon Bowen

Ash clouds from Mount St. Helen, taken by Richard Gordon Bowen