07:14 PM PST on Tuesday, March 8, 2005
KING5.com
VANCOUVER, Wash. - A large plume of steam rising up to 36,000 feet was being emitted Tuesday afternoon from the crater of Mount St. Helens.
It could be seen from miles around, including Portland, Oregon, and was moving northeast.
The eruption occurred at about 5:20 p.m. Tuesday.
The plume was accompanied by an earthquake of about 2.0 magnitude, according to Bill Steele, coordinator of the Pacific Northwest Seismograph Network at the University of Washington.
Steele said he did not believe the explosion had increased the risk of a significant eruption and noted that recent flights over the volcano's crater did not reveal high levels of gases.
Steele said the ash burst may have been triggered by partial collapse of a lava dome in the crater, which has been growing steadily over the last several months.
"Until we get a better view in the crater we won't know," Steele said.
Mike Fergus, FAA, said he believes the cloud was mostly steam and did not present a danger to airplanes in the area.
The USGS Cascades Volcano Observatory lost radio signals from three monitoring stations in the crater soon after the event started. The cause of the outage won't be known until scientists can visit the crater Wednesday to assess the situation, weather permitting.
An ashfall advisory is in effect until 9 p.m. for the south Washington Cascade foothills and the south Washington Cascades.
The winds are expected to take the ash plume to the east and north of Mount St. Helens, with the heaviest amounts to fall in Skamania County, and lighter amounts in Cowlitz County.
Breathing volcanic ash can be dangerous to many people, especially those with respiratory problems.
The 9,677-foot volcano in southwest Washington rumbled to life again last fall, pumping out lava as the mountain nears the 25th anniversary of the devastating eruption of May 18, 1980, that killed 57 people.
This latest volcanic burp from the mountain comes just after the state Board on Geographic Names unanimously chose Tulutson, the Cowlitz Indian word for ice, as the name for the glacier that has grown inside the mountain's crater.
Informant: Anna Webb
Mount St.Helens Unexpectedly Explodes
March 8th 2005
EARTH CHANGES TV NEWSLETTER
by Mitch Battros - ECTV
At 5:25 PM (Pacific) Mount St. Helens erupted spewing ash and rock six miles into the sky. Airlines have been ordered to stay clear of a 20 mile radius. The ash explosion happened around 5:25 p.m., about an hour after a 2.0 magnitude quake rumbled on the east side of the mountain, said Bill Steele, coordinator of the Pacific Northwest Seismograph Network at the University of Washington.
Steele said he did not believe the explosion had increased the risk of a significant eruption and noted that recent flights over the volcano's crater did not reveal high levels of gases.
Steele said the ash burst may have been triggered by partial collapse of a lava dome in the crater, which has been growing steadily over the last several months. "Until we get a better view in the crater we won't know," Steele said.
Steele said there had been no increase in quake activity before the explosion. "The seismicity had been continuing just as it had been," she said.
On May 18, 1980, the volcano 100 miles south of Seattle blew its top, killing 57 people and covered the region with gritty ash.
Tuesday March 8th – Bill Steele – Seismology Lab Coordinator for the Pacific Northwest Seismograph Network (PNSN) at the University of Washington Department of Earth and Space Sciences. Mr. Steele directs the educational outreach program for the network, and serves as Public Information Officer (PIO) for both the PNSN and for many USGS earthquake-related research activities in the Pacific Northwest. Directing the expansion of the PNSN outreach program, he has worked extensively with private and public sector organizations to better address their information needs and to build coalitions to meet mutual concerns. PNSN Website:
http://www.geophys.washington.edu/SEIS/PNSN/
