Good morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Wednesday, February 24, at 6:30 AM. Today’s advisory is sponsored by Spark 1 and Cooke City Super 8/Bearclaw Bob’s. This advisory does not apply to operating ski areas.
At 5 a.m. skies are clear, mountain temperatures are in the low teens and winds are from the west at 15 mph. This morning will be mostly sunny with light west winds and temperatures reaching the mid-30s. This afternoon high clouds coupled with a light breeze will keep snow surface temperatures cool enough to ward off wet avalanches. Tonight will be mostly clear and temperatures will dip into the teens as the high pressure continues.
Southern Madison Range Southern Gallatin Range
Lionhead area near West Yellowstone Cooke City
In the southern half of our advisory area we are concerned with a weak layer of buried surface hoar. These feathery grains of frozen dew are buried 1-3 feet deep and were responsible for a rash of avalanche activity over the weekend. Many slides outside Cooke City were triggered by skiers and snowmobilers. I investigated one of these on Monday (video, photo) on the north side of Scotch Bonnet. In the Lionhead area and southern Madison Range snowmobilers triggered avalanches that released on this layer too (Black Bear, Lionhead, Cabin Creek). Karl Birkeland dug a snowpit in Bacon Rind and made a video of his test which shows weakness and instability.
The surface hoar is visible as a grey stripe in the snowpit wall (photo). It is found in all the southern mountain ranges, but not on every slope. This variability means homework is in order. Dig down, and if you see it go somewhere else. If you do not find it, dig again in another spot to confirm it is not there. Surface hoar can avalanche over a month after being buried. Given the possibility of triggering avalanches, the danger is rated MODERATE on all slopes today.
Bridger Range Northern Madison Range Northern Gallatin Range
I toured north of Bridger Bowl to Wolverine Bowl yesterday and found a five foot deep, stable snowpack. In our snowpit we were unable to get breaks in our stability tests which lined up with other observations from Alex, Eric and other skiers. There are still slopes with weak snow at the ground (Mt. Ellis), but without a fresh load of new snow avalanches are unlikely. To be clear, unlikely does not mean impossible so do not throw caution to the wind. Ski one at a time and carry rescue gear…you will never be sorry you did. For today, the avalanche danger is rated LOW.
Alex will issue the next advisory tomorrow morning by 7:30 a.m. If you have any snowpack or avalanche observations to share, drop us a line at mtavalanche@gmail.com or leave a message at 587-6984.
EVENTS and AVALANCHE EDUCATION
A complete calendar of classes can be found HERE.
TONIGHT, Bozeman: Wednesday, February 24, 6-7 p.m. 1-hr Avalanche Awareness, Roskie Hall, MSU.