Mount St. Helens is a volcano located in Washington state. In May 1980, it erupted in a massive explosion, causing widespread destruction. The eruption began with an earthquake that triggered a landslide on the north side of the mountain. This removed pressure that had been building inside. Ash and gases were released at over 300 mph, reaching as high as 10 miles into the sky. The eruption killed 57 people and destroyed hundreds of square miles of forest. It removed over 1,300 feet from the mountain's peak. Today, the area is recovering but the powerful eruption is not forgotten.