Mount St. Helens is basically an active volcano that is located in the Skamania County in the Washington area. It is located south of Seattle and Northeast of Portland, Oregon.
This mountain has been named after a British Diplomat Lord St. Helens because he was the first one to take a survey of this area. This area is well known for its volcanic explosions.
The biggest eruption of this volcano happened on May 18, 1980. It is the most deadliest volcano in the history of United States. It resulted in deaths of around 57 people, destruction of 250 homes, 47 bridges, railways and highways. It also resulted in an avalanche that reduced the elevation of the mountain's summit.
It was also hit by an earthquake that reached an intensity of 5.1. It lasted for 9 hours and changed the total landscape of the area.