|2009 Portland GSA Annual Meeting (18-21 October 2009)|
|Paper No. 280-7|
|Presentation Time: 3:30 PM-3:50 PM|
MASSIVE DEBRIS FLOW EVENTS ON PACIFIC NORTHWEST VOLCANOES, NOVEMBER, 2006: AS THE CLIMATE CHANGES, MORE DEBRIS FLOW EVENTS TO COME
BURNS, Scott F.1, PIROT, Rachel1, SOBIESZCZYK, Steven2, and WILLIAMS, Kendra1, (1) Department of Geology, Portland State University, P.O. Box 751, Portland, OR 97207-0751, firstname.lastname@example.org, (2) Geology Department, Portland State University, PO Box 751, Portland, OR 97207|
During the second week of November, 2006 a warm, wet air mass, locally called the “Pineapple Express” hit Oregon and Washington and dumped over 50 cm rain onto the volcanoes within 36 hours before there was snow cover. It mobilized the abundant sediment on the slopes of the volcanoes and created many devastating debris flows. The amount of available sediment on the slopes has increased in recent years as glaciers have retreated, exposing the inside of lateral moraines. Mt. Hood was the most devastated with 7 of 11 major drainages producing significant debris flows. Eliot Creek and White River produced extensive debris flows that measured well over 2 million cubic meters each and closed major highways in the region for weeks. A large delta formed in the Columbia River at Hood River resulting from the debris flows. At Mt. Rainier the southwest drainages were hit hard. Kautz Creek rerouted. The Nisqually River enlarged greatly in size and almost undercut the Longmire emergency response headquarters. The Sunshine Campground disappeared. At Mt. St. Helens, the road to Lava Canyon was washed out in two places. Milk Creek was the major debris flow on Mt. Jefferson. On Mt. Adams, many debris flows were generated in the drainages of Salt Creek, Adams Creek and the Big Muddy. The largest debris flow collapsed the moraine at Crofton Ridge. As the climate continues to change, we will see more large debris flows as these air masses arrive before snow cover can shield their impact on the volcanoes.
2009 Portland GSA Annual Meeting (18-21 October 2009)
General Information for this Meeting
|Session No. 280|
Debris Flows II
Oregon Convention Center: E147/148
1:30 PM-5:30 PM, Wednesday, 21 October 2009
Geological Society of America Abstracts with Programs, Vol. 41, No. 7, p. 716
© Copyright 2009 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.