Mount Spurr is not the kind of lava-spewing volcano familiar from Hawaii, but instead has historically ejected huge plumes of volcanic ash as high as 45,000 feet into the atmosphere, disrupting air travel between the United States and Asia via the great circle routes that link places like New York and Tokyo by following the curve of the earth.

Mount Spurr is part of the Ring of Fire, located in southern Alaska. The mountain is a stratovolcano, which means it has steep slopes and is known for its explosive eruptions. The last major eruption occurred in 1992,