Good morning. This is Doug Chabot with the Gallatin National Forest Avalanche Forecast on Thanksgiving Day, November 24th at 7:00 a.m. This information is sponsored by World Boards and Archer Construction. This forecast does not apply to operating ski areas.
*Note: Bridger Bowl Ski Area is closed and there is no avalanche control or ski patrol services. Backcountry conditions exist. Please don’t ski over hoses and power cords, stay off chairlifts, and give snowcats and snowmobiles plenty of room.
In the last 24 hours the mountains around Bozeman, Big Sky and Cooke City picked up 5-7” of new snow. South of Big Sky to West Yellowstone and Island Park 2-3” fell. This morning under clear skies mountain temperatures are in the low teens and wind is blowing westerly at 10 mph with gusts to 20 mph. Today will be sunny and temperatures will warm to the high 20s F with light westerly wind.
The storm dropped 8-11" of snow around Bozeman, Big Sky, Cooke City and Taylor Fork, and 3-5” around West Yellowstone. In some areas this new snow fell onto a weak surface (facets). On slopes that were drifted by the wind it remains possible to trigger avalanches. Alex found this avalanche recipe (slab sitting a weak layer) in Bridger Bowl yesterday. He intentionally triggered a 20-foot wide, 6-8” deep, soft slab of wind blown snow. It ran 250 feet and broke on the faceted, old surface (details and photos). Additionally, on high elevation sloples, especially north facing, there could be weak snow at the ground. As evidence, a large avalanche on Hyalite Peak last Friday broke on this basal layer (photo and details). We do not believe this deep instability to be widespread, but we will be hunting for it.
Our main avalanche concern is wind drifted snow. Shooting cracks are signs the snow is unstable, and any avalanche, no matter how small, is bullseye data to stay off steep terrain. Digging and testing the snow is fruitful since there are not many layers. With 2-3 feet of snow in the mountains, travel is getting easier which means our exposure to avalanche terrain is rising. Ice climbers and hunters need to be extra careful crossing wind-loaded gullies.
Today, triggering avalanches is possible and the avalanche danger is rated MODERATE.
Dave will issue the next forecast tomorrow morning. If you get out, please share avalanche, snowpack or weather observations via our website, email (mtavalanche@gmail.com), phone (406-587-6984), or Instagram (#gnfacobs).
About 2-3” fell in the mountains around Island Park. This new snow fell onto a surface of weaker snow (facets). On Monday a sledder had cracks propagating in wind drifted snow on Reas Peak which was a warning that some slopes were unstable (photo). Digging and testing the snow is fruitful since there are not many layers (video). With 3-4 feet of snow in the mountains, travel is getting easier which means our exposure to avalanche terrain is rising.
Upcoming Avalanche Education and Events
Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar.
Tuesday, November 29, 6 p.m. Sidecountry Avalanche Awareness for Families (and Friends) at Story Mill Park. Free.
We are offering an Avalanche Fundamentals with Field Session course for skiers in December and January, and snowmobilers in early January. Sign up early before they fill up.
Tuesday, December 13, 6 p.m. Avalanche Awareness + Beacons at Story Mill Park. Free.
The Friends of the Avalanche Center are hosting the Powder Blast Fundraiser. Your donations support free and low-cost avalanche education, beacon checkers at trailheads, beacon parks, weather stations, and GNFAC programs! The Friends of GNFAC launched an online GoFundMe campaign. Please consider a donation, and we look forward to having an in-person event again in the future.
