Mount St Helens
/ˌmaʊnt snt ˈhelənz/
/ˌmaʊnt seɪnt ˈhelənz/
- a volcano (= a mountain from the top of which melted rock and gases can explode with great force) in the Cascade Range of the US state of Washington. It erupted in 1980 for the first time in 120 years killing about 60 people, and causing damage to the surrounding area. The explosion reduced the height of the mountain by over 1 000 feet/300 metres. There have been several weaker eruptions since.