AK's Redoubt Volcano Keeping Scientists and Public on Guard

Small plume of ash, steam, and gas rises from the summit crater of Redoubt volcano, Alaska, on March 15, 2009. The plume was observed during an observation and gas-measurement flight by scientists of the Alaska Volcano Observatory, probably the result of a steam explosion in the volcano's active shallow hydrothermal system. More explosions could occur with little or no warning and generate ash-rich clouds higher than 20,000 feet above sea level. Photograph by Alaska Volcano Observatory.