Alaska Volcano Erupts, Sends Ash 7 Miles High

Redoubt volcano southwest of Anchorage shook with thousands of small earthquakes Thursday, then erupted and shot a cloud of ash 7 miles high.

The eruption of the 10,197-foot volcano began shortly after 10 a.m. and lasted for an hour, U.S. Geological Survey geologist Don Richter said.

“It’s steaming vigorously,” volcanologist Tom Miller said on his return from a flight to the volcano 100 miles southwest of Anchorage. “There’s steady pulsating and a steam cloud but no more ash.”

He said there was no immediate evidence of a lava flow.

The eruption followed 24 hours of constant warning tremors, which calmed down after the eruption ended, then picked up again, Miller said. Scientists were unable to predict whether Redoubt would settle down or explode again.

Workers were evacuated from the Drift River crude oil storage site 22 miles from the exploding mountain, but there appeared to be no danger to the facility and 37 million gallons of oil stored there from Cook Inlet drilling platforms, Cook Inlet Pipe Line Co. manager Harold Mouser said. He said no tankers were due to pick up oil at the facility until next week.

The ash plume--which shot 35,000 feet above the 2-mile-high mountain--was carried toward Anchorage by strong winds, National Weather Service meteorologist Bob Hopkins said. But the ash cloud skirted Anchorage and dusted towns beyond the city.

Wasilla and other small cities north of Anchorage received light ash fall, said Kevin Koechlein, emergency services coordinator for the Matanuska-Susitna Borough. “I have a pile of it sitting on my desk,” he said of the fine, sandy ash.

Terrie Godfrey of the Wasilla Chamber of Commerce said that the ash is “thick enough that I had to turn my windshield wipers on. There’s little bitty speckles.”

Radio stations warned people with respiratory problems to remain inside because of the ash.

Ash was falling over unpopulated mountainous areas also, and some of the debris was dissipating in the atmosphere, officials said.

The Federal Aviation Administration issued flight restrictions, warning pilots to steer 15 miles clear of Redoubt because ash can damage jet engines. Anchorage International Airport officials reported no interference with flights such as occurred in 1986, when Augustine volcano erupted.

Miller said his surveillance flight showed that the volcano blew a hole in a vent left over from its last eruption more than 20 years ago. Redoubt erupted in 1902, 1933 and several times during a period of activity from 1965 to 1968.

He said there was no indication that the eruption and heavy steaming were suddenly melting snow on the mountain, which occurred during Redoubt’s 1966 eruption and caused flash flooding on the Drift River. The oil storage area there, built after Redoubt’s last eruption, is protected by dikes in case of new flooding, Mouser said.

A dozen oil workers at Drift River were the closest people to the volcano, and Mouser said they would stay out of the area until it is safe to return.

Redoubt gave short notice that it might explode. The mountain, visible from Anchorage on a clear day, let off a little steam last week, as all active volcanoes do occasionally. But it was not until seismic monitors showed constant earth tremors Wednesday and Thursday that geologists and emergency services officials mobilized.