Mount Adams rock and snow avalanche, Aug 1, 2008

[Amar_Andalkar]

How did this not make the Seattle news? There was a major rock and snow avalanche from the cliffs above the Avalanche Glacier on the west side of Mount Adams, at 7:43 AM PDT on August 1, 2008:

 

http://daveslandslideblog.blogspot.com/2008/08/mount-adams-rock-and-snow-avalanche.html

http://www.oregonlive.com/environment/index.ssf/2008/08/major_avalanche_reshapes_mount.html

 

Major avalanche reworks Mount Adams

by Michael Milstein, The Oregonian

Wednesday August 06, 2008, 2:59 PM

 

A two-mile-long avalanche of ice and rocks large enough to rattle seismometers has reworked the southwest face of Mount Adams.

 

The volcano is usually very quiet, with few of the tremors that occur occasionally at other Cascade volcanoes such as Mount Hood. So the seismic signal from Mount Adams on Aug. 1 stood out to Cynthia Gardner of the Cascades Volcano Observatory in Vancouver, who first noticed it. "It is a very large signal at a volcano that has a very quiet background," she told The Oregonian on Wednesday.

 

She passed on her observations to researchers at the Pacific Northwest Seismic Network at the University of Washington. There, seismologist Robert Norris recognized it as the likely signature of a major avalanche or rockfall, Norris said. He relayed the information to Darryl Lloyd, a Hood River photographer and longtime authority on the Mount Adams region. Lloyd reported back that indeed a major avalanche beginning at Avalanche Glacier had tumbled about two miles down the mountain.

 

The Avalanche Glacier area of the mountain is aptly named, as it has released major avalanches in the past. A rock-and-ice avalanche from the same area in August 1997 ran about three miles down the mountain. It contained an estimated 5 million cubic meters of material and was the largest avalanche in the Cascades since one on Mount Rainier in 1963, according to the Cascades Volcano Observatory. The avalanche this month was not that big, Lloyd said. It was more akin to a 1983 avalanche from the same area.

 

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[danhelmstadter]

probably just warm temps helping to trigger it?

 

Amar - I assume that's the same headwall you skied earlier this year. You had mentioned that the coverage on that particular aspect of Adams was unusually deep. Maybe all the extra snow melt percolated, and got glacier/sand/rock real wet and lubed - setting the stage for a big release?

 

It kinda looks like it was initially part of the glacier that released, but definitely hard to tell from that one photo.

Edited August 9, 2008 by danhelmstadter

[pc313]

I know it happen 3 or 4 yr's ago,and was felt in Trout Lake!!

Norm