North flank of Mount Redoubt and low-level vapor plume -Picture Date: January 31, 2009 Image Creator: Waythomas, Chris Image courtesy of AVO/USGS.

Alaska’s Mount Redoubt volcano is about to blow its top say seismic experts. An eruption is expected within days or weeks according to the latest activity report, which tells of a vapor plume rising above the volcano’s summit crater.

Redoubt, located on the Kenai Peninsula, 106 miles southwest of Anchorage, is one of 130 volcanoes in the “Land of the Midnight Sun.”

Scientists from the Alaska Volcano Observatory (AVO) are monitoring events round-the-clock at Redoubt, which has been assessed by the U.S. Geological Survey (USGS) as one of the nation’s highest-threat volcanoes.

Location of Redoubt volcano, in relationship to surrounding towns, roads, and other volcanoes. Picture Date: September 26, 2008 Image Creator: Schaefer, Janet, Image Creator:Image courtesy of the AVO/ADGGS.

Mount Redoubt’s last eruption stretched from late 1989 into 1990. The series of eruptions were the second most costly in the history of the United States, and had significant impact on the aviation and oil industries, as well as the people of the Kenai Peninsula.

On December 15, 1989, a Boeing 747 flying 150 miles northeast of Anchorage encountered an ash cloud from Redoubt Volcano and lost power in all four jet engines. The plane, with 231 passengers aboard, lost more than 9,800 feet of elevation before the flight crew was able to restart the engines. After landing, it was determined the airplane had suffered about $80 million in damage.

Since 1700, at least 41 volcanoes in Alaska have erupted, some of them as many as 25 times, according to an Ash Alert brochure linked from the Alaska Division of Home Security and Emergency Management.

Ashfall is one of the greatest dangers associated with volcanic eruptions. According to the USGS website, volcanic ash consists of tiny jagged pieces of rock and glass. Ash is hard, abrasive, mildly corrosive, conducts electricity when wet, and does not dissolve in water. Ash is spread over broad areas by wind. During an ashfall, daylight can change to complete darkness. Accompanied by rain and lightning, the gritty ash can also lead to power outages, prevent communications, and disorient people.

The AVO website states that on the Kenai Peninsula, during the 1989-90 eruptions, schools were closed and some individuals experienced respiratory problems. Drifting ash clouds disrupted air traffic as far away as Texas. Ash also interrupted commercial air traffic into and out of Anchorage, and mudflows from the volcano threatened an oil storage facility near Cook Inlet.