Fine granules of ash drifted across parts of Alaska Friday in the aftermath of the eruption of Redoubt Volcano, which blew its top with little warning after lying dormant since 1968.
The volcano in southwest Alaska awoke Thursday with an eruption that sent a plume of ash 7 miles high, prompting warnings to airline pilots to stay clear of the area and the evacuation of workers at a crude oil storage site 22 miles from the mountain.Scientists monitoring the volcano said they were unable to predict whether Redoubt would explode anew.
Volcanologist Tom Miller, who flew to the site 100 miles southwest of Anchorage, said: "It's steaming vigorously. There's steady pulsating and a steam cloud but no more ash." There was also no flow of lava.
The 10,197-foot volcano went into what is known as a "harmonic tremor," a constant shaking prompted by hot, moving liquids, before erupting at 10:13 a.m. Thursday in an almost hourlong explosion that sent a plume of smoke and ash billowing 35,000 feet high, U.S. Geological Survey geologist Don Richter said.
By late Thursday, the volcano seemed to have all but exhausted itself save for its vent, just below the mountain's summit, where bursts of steam packed enough energy to register on a seismic monitor, seismologist Charlotte Rowe said.
The ash plume - which shot 5 miles above the 2-mile-high mountain - was carried toward Anchorage by strong winds, National Weather Service meteorologist Bob Hopkins said, but the high ash cloud skirted Anchorage and dusted towns beyond Anchorage with light ash.
In Vancouver, Wash., meanwhile, scientists reported that Mount St. Helens, which killed 57 people when it erupted in 1980, spewed a fine layer of ash last week inside its mile-wide crater in the volcano's most significant sign of life in more than three years.
The ash emission apparently occurred as a swarm of small earthquakes shook the southwestern Washington peak, said geologist Steve Brantley of the Cascades Volcano Observatory.