Dwight R. Crandell dies at 86; volcanologist helped predict 1980 eruption of Mt. St. Helens

Dwight R. "Rocky" Crandell, a U.S. Geological Survey volcanologist whose persistent tracking of deep layers of mud led to a pioneering reassessment of volcano hazards in the Pacific Northwest, died April 6 at a hospice in Wheat Ridge, Colo., from a heart attack. He was 86.

April 19, 2009