Alaska’s Mount Redoubt Erupts Six Times
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Alaska’s Mount Redoubt volcano erupted Sunday night, sending an ash plume more than nine miles into the air in the volcano’s first emissions in nearly 20 years. Since then, there have been five more explosions; the latest, on Monday night, shot an ash plume into the air that was 40,000 to 50,000 feet high.
The volcano has been relatively quiet since, but that is not expected to continue, said Stephanie Prejean, a research geologist with the U.S. Geological Survey. The last time Redoubt erupted in 1989, there were more than 20 explosions as magma pushed to the surface and formed domes that later collapsed and sent ash plumes into the air.
“This is very typical for volcanoes of this type,” Prejean said. “These domes ooze out of the earth. They are very thick, like toothpaste.” She said that when this type of volcano is in the dome-building phase, as it is now, things can happen quickly, making it difficult to warn people about any explosions.
Ash from Alaska’s volcanos is like a rock fragment with jagged edges and has been used as an industrial abrasive. It can injure skin, eyes and breathing passages. The young, the elderly and people with respiratory problems are especially susceptible to ash-related health problems. Ash can also cause damage engines in planes, cars and other vehicles.
Mud flows from the volcano have downed hundreds of trees and filled the Drift River Valley with debris, said USGS research geologist Kristy Wallace. Ash collected near the volcano is fairly coarse, with some pieces measuring 3 inches across, she said. There is evidence that magma has reached the surface.
The first eruption, in a sparsely populated area across Cook Inlet from the Kenai Peninsula, occurred at 10:38 p.m. Sunday, and the sixth happened on Monday night, according to the Alaska Volcano Observatory. The wind was taking the ash cloud away from Anchorage, toward Willow and Talkneetna, near Mount McKinley, North America’s largest mountain in Denali National Park.
Alaska Airlines resumed flights to and from Alaska on Tuesday after ash clouds from eruptions this week forced the cancellation of 35 flights. The airline’s jets at the Anchorage airport were wrapped in a protective plastic sealant and unsealed Tuesday morning. The airline says the sealant protects aircraft from abrasive ash particles, which post a significant danger to engines.
The 10,200-foot Redoubt Volcano, which is roughly 100 miles southwest of Anchorage, last erupted during a four-month period from 1989 to 1990. In its final eruption, Redoubt sent ash 150 miles away into the path of a KLM jet, causing its four engines to flame out. The jet dropped more than two miles before the crew was able to restart all engines and land safely. The plane required $80 million in repairs.
Mount Redoubt became restless again earlier this year, with the Alaska Volcano Observatory warning in late January that an eruption could occur at any time. A steam plume rising about 1,000 feet above the mountain peak was observed Saturday, and increased earthquake activity over the previous 48 hours prompted scientists to raise the alert level for the volcano on Sunday. On Sunday morning, 40 to 50 earthquakes were being recorded every hour.
Dave Stricklan, a hydrometeorogical technician with the National Weather Service, expects very fine ash to be suspended in the atmosphere for quite some time. “Just kind of a light dusting,” he said. He explained that the significant amount of ash probably dropped immediately, right down the side of the volcano.
“The heavier stuff drops out very quickly, and then the other stuff filters out. There’s going to be a very fine amount of it that’s going to be suspended in the atmosphere.” he said. “The finer ash is going to travel farther, and any ash can effect aviation safety.”
Associated Press Writer Mark Thiessen in Anchorage contributed to this report.
For more information: Alaska Volcano Observatory
