"The 1989-90 eruption of Redoubt Volcano, 177 km southwest of Anchorage, Alaska, began on December 14, 1989, less than 24 hours after a swarm of earthquakes struck beneath the volcano. A huge cloud of ash heralded the volcano's fourth and most damaging eruption of this century. Volcanic ash generated by numerous explosive episodes from December 1989 through April 1990 caused significant damage to aircraft, severely disrupted air traffic above southern Alaska, and resulted in local power outages and school closures. The explosions produced hot, fast-moving clouds of ash, rock debris, and gas (pyroclastic flows) that swept across Redoubt's heavily glaciated north flank. These events triggered massive debris flows in Drift River valley that threatened an oil tanker terminal near the river's mouth. Partial flooding of the terminal compound on two occasions forced authorities to modify its operating procedures, which temporarily curtailed oil production from 10 platforms in Cook Inlet. The damage and loss of revenue from ash and debris flows are estimated to total more than $100 million, which makes this the second most costly volcanic eruption in the history of the United States, exceeded only by the 1980 eruption of Mount St. Helens in Washington."
U.S. Geological Survey Circular 1061
Government Publishing Office: http://www.gpo.gov/