Good Morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Wednesday, December 8, at 7:30 a.m. Alpine Orthopedics, in cooperation with the Friends of the Avalanche Center, sponsor today’s advisory. This advisory does not apply to operating ski areas.
After a sunny day with temperatures in the high 20s, clouds rolled in and winds started to pick up last night. Ridgetop winds are southwest at 15-25 mph and will gust into the mid 30s later this afternoon. Today will be cloudy and windy with temperatures in the mid 20s. Most importantly, a moist westerly flow will bring snow showers and drop 1-2 inches in the north and 2-4 inches in the southern ranges.
The Bridger, Gallatin and Madison Ranges, the Lionhead area near West Yellowstone, the mountains around Cooke City and the Washburn Range:
Mark skied in the Bacon Rind area of the southern Madison Range yesterday. He and his partner found 2-3 feet of stable, supportable snow. Skiers in Beehive Basin in the northern Madison Range found similar conditions as did Eric on Hyalite Peak on Monday. I was in Cooke City Sunday and Monday and was pleased to find good stability too (photo). At the Yellowstone Club, the patrol ran avalanche control for the first time on a snowpack that resembles the backcountry. They had no deep avalanches, just slides confined to wind-loaded slopes. The Patrol Director said, “It’s refreshing not to be in knee deep facets this time of year.” Here, here! Without a persistent weak layer in the snowpack I’m a happy forecaster.
I have some minor concerns with the current state of affairs. The winds are picking up and there’s plenty of soft snow to move around. I expect wind drifts to form near the ridge lines where even a thin wind slab could ruin your day if it slid. There are also isolated spots where faceted snow near the ground is occasionally breaking clean in our stability tests. Eric found this in the northern Bridgers and I found it outside Cooke City, both on northerly facing slopes.
And then there’s surface hoar (photos). These feathery grains are blanketing large portions of our advisory area. Coupled with smaller facets, this will become a prominent weak layer if it gets buried. The wind may knock it down beforehand, but I’m bracing myself for it to survive and avalanche. Like unwelcome relatives over the holidays, buried surface hoar causes me stress, is unpredictable and never seems to go away when I want it to.
Given my concerns with potential wind-loading and isolated instability, for today I’m rating the avalanche danger MODERATE on slopes steeper than 35 degrees and LOW elsewhere.
Although it’s outside of our forecast area, I received a relevant observation for the northern Absaroka Range southeast of Livingston. Skiers found a remarkably different snowpack than what we’ve been reporting. Shallow areas failed to support an isolated column and slopes four feet deep were not that stable either. This is a great reminder that different avalanche dragons lurk in different ranges.
Mark will issue the next advisory tomorrow morning at 7:30 a.m. If you have any snowpack or avalanche observations, drop us a line at mtavalanche@gmail.com or call us at 587-6984.
Upcoming Avalanche Education
“How Much Did It Snow?” Join Lucas Zukiewicz from the Montana Snow Survey for a FREE presentation/discussion on the SNOTEL system in SW Montana. The discussion will cover how to access SNOTEL information and interpret the data for snow and weather conditions. Saturday, December 11, 7:30pm – 8:30pm at World Boards.
Avalanche Awareness for Snowmobilers in West Yellowstone Thursday, December 16th from 12 p.m. to 5 p.m (lectures), with an all day field day Friday, December 17th. For more information check out http://www.mtavalanche.com/education/classes/snowmobilers or call us at 587-6984.
Other News
This year REI has chosen Friends of GNFAC as their charity of choice. By making a donation through REI you can help The Friends continue to support the Avalanche Center and promote avalanche education throughout southwest MT.