Volcano Update from Archive

Friday, March 20, 2009 11:06 AM AKDT (Friday, March 20, 2009 1906 UTC)

Sanford Volcano
62°12'48" N 144°7'46" W, Summit Elevation 16237 ft (4949 m)
Current Volcano Alert Level: UNASSIGNED
Current Aviation Color Code: UNASSIGNED

For the past several days, residents of the Copper River Basin have observed and reported a persistent, white cloud streaming from the summit of Mt. Sanford and extending for up to several tens of miles to the south. The cloud was easily visible in Gulkana Weather webcam images. AVO analysis of satellite images over the last several days shows that similar clouds have been intermittently streaming from many of the higher mountain peaks in the Wrangells. These clouds are a weather phenomenon and not related to volcanic activity. The most likely explanation for generation of these clouds is the rise and cooling of moist air as regional air masses pass over the mountains. Local geopgraphic features and solar radiation on the peaks contributes to the presence of moist air that subsequently condenses to create and feed these clouds.

Mt. Sanford, located 45 miles (72 km) east of Glennallen, Alaska, is a dissected complex shield volcano and the highest volcano (16,237 ft; 4,949 m) in the Pleistocene Wrangell volcanic field. Its south face has a vertical relief (cliff) of over 8,000 feet (2,400 m). This precipitous wall is the source of nearly constant rock, snow, and ice-falls onto the Sanford Glacier, and on occasion these falls produce minor, local vapor plumes. There is no record of historical eruptive activity at Mt. Sanford, and the youngest lava flows are estimated to be 100,000 years old.

Tom Murray, Scientist-in-Charge, USGS

tlmurray@usgs.gov (907) 786-7497

Steve McNutt, Coordinating Scientist, UAF

steve@giseis.alaska.edu (907) 474-7131

The Alaska Volcano Observatory is a cooperative program of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys.