The sheer scale of the eruption of Mount St. Helens on May 18, 1980, staggers the imagination. The volcano spewed 540 million tons of ash over 22,000 square miles, killing at least 57 people, 11,000 hares and 5,000 black-tailed deer, and destroying 4.7 billion board feet of timber. Rob Carson offers a readable, straightforward account of the eruption and its aftermath, including the unsuccessful attempts by the Army Corps of Engineers and the Forestry Service to remove tens of millions of tons of ash and debris. In one ill-advised effort, Forestry agents dumped tons of grass seed and fertilizer on acres of sterile ash: The seeds failed to germinate but provided food for hordes of field mice that hampered later efforts at reforestation. Carson concludes with dire predictions from geologists that the 1980 eruption was part of a clearly documented pattern: Further activity can be expected from Mount St. Helens and other volcanos in the Cascades range, including Mt. Rainier, Mt. Lassen and Mt. Shasta.