After two months of restlessness and a day of heightened earthquake activity, Alaska’s Mount Redoubt Volcano erupted explosively on Sunday, March 22, 2009, at 10:38 p.m. Alaska Daylight Time, according to the Alaska Volcano Observatory. Overnight, four additional large eruptions occurred, the fifth one larger than the previous ones. Scientists estimated the plume reached a height of 50,000 feet above sea level. As the ash spread north and northeast, ashfall advisories were issued for communities north of Mt. Redoubt. Geologists warned of the possibility of mudflows and debris avalanches from melting ice on the mountain’s summit.
These eruptions all occurred in darkness, which means that photo-like images from satellites weren’t possible. But the plumes were detectable in thermal infrared imagery captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra (top). Temperatures range from warmer (black) to colder (white).
This and more information is available from the NASA Earth Observatory website here.
(NASA images created by Jesse Allen, using data provided courtesy of the MODIS Rapid Response team. Caption by Rebecca Lindsey.)