Mount St. Helens

The deadliest and economically most destructive eruption occurred on May 18th, 1980.

An excerpt from the article 21 facts about Mount St. Helens
It took the lives of 57 people and destroyed homes, bridges, roads, and railroads. The eruption lowered the mountain’s summit to 2,549 meters (from the previous 2,950 meters). The blast was triggered by a 5,1-magnitude earthquake followed by a debris avalanche. Within minutes, an area of 595 square kilometers was destroyed. The rising level of river waters caused flooding in the surrounding valleys.