USGS: Pond at base of Mount Hood glacier much larger than normal, could lead to debris flow
VANCOUVER, Wash. (KTVZ) -- Scientists recently found a pond at the base of a glacier on Mount Hood was much larger than in past years, which if released suddenly could generate a debris flow down the White River. But they added that the topography and estimated amount of water, impacts to populated areas are not expected.
Here's Friday's information, part of a weekly update from the U.S. Geological Survey's Cascades Volcano Observatory:
On October 6, USGS scientists performing a routine helicopter observation flight at Mount Hood noticed that a seasonal meltwater pond at the base of the Coalman Glacier was significantly larger than in previous years.
The pond lies in a basin bounded by Crater Rock, cliffs extending down from the summit, and Devil’s Kitchen, an earthen berm composed of hydrothermally altered rock and glacial moraine material.
Devil’s Kitchen is a long-lived feature and appears stable, based on current observations.
The pond’s water volume is unknown but is estimated to be on the order of ~50,000 cubic meters, roughly equivalent to 20 Olympic-sized swimming pools.
A water sample collected last week had a provisional measured pH of 4, which is similar to the pH of black coffee, indicating mildly acidic conditions.
If all the water were released suddenly, it could generate a debris flow down the White River with the potential to reach the Highway 35 bridge.
Topography would prevent the flow from traveling down the Sandy River or toward Timberline and Government Camp. Based on current estimates of the pond’s water volume, impacts to populated areas are not expected.
USGS Cascades Volcano Observatory scientists are working with the U.S. Forest Service, the National Weather Service, Portland Mountain Rescue, and other agencies to make additional measurements and assess the stability of the meltwater pond. CVO will issue further updates as conditions warrant.
Here's the rest of Friday's acivity update:
All volcanoes in the Cascade Range of Washington and Oregon are at normal background activity levels. These include Mount Baker, Glacier Peak, Mount Rainier, Mount St. Helens, and Mount Adams in Washington State and Mount Hood, Mount Jefferson, Three Sisters, Newberry, and Crater Lake in Oregon.
Over the past week, there were small earthquakes detected at Mount St. Helens. Field crews conducted a gravity survey at Mount Hood, installed sensors at Spirit Lake near Mount St. Helens, and made improvements to monitoring stations at Mount Adams. Analysis of routine gas flight measurements at Mount Adams, Mount St. Helens, and Mount Hood showed normal background levels of degassing.
