This stratovolcano erupted in 1980 in the United States. Although there were warnings of its impending eruption, it still killed dozens, partly because it first blew sideways, producing a monstrous landslide. This volcano is:.

Mt. St. Helens.

Explanation:

This stratovolcano erupted in 1980 in the United States. Although there were warnings of its impending eruption, it still killed dozens, partly because it first blew sideways, producing a monstrous landslide. This volcano is Mt. St. Helens. Mount St. Helens is an active Volcano located in Washington. It is believed to have been formed 275 thousand years ago, it is an explosive dacite volcano. During the 1980 eruption of the volcano, it first blew off from the side and later the summit was removed leaving a horse-shoe shaped crater.