Good morning. This is Ian Hoyer with pre-season avalanche, weather and event information for the Gallatin National Forest Avalanche Center on Black Friday, November 26th. This information is sponsored by Yellowstone Club Community Foundation and Montana State Parks. We will update this bulletin on Monday, November 29th.
Only an inch or two of new snow fell over the last two days. Moderate southwest to northwest winds have been gusting to 35-50 mph. This morning temperatures in the Bridgers have risen into the high 30s and 40s F, while the rest of the advisory is in the teens and 20s F. Temperatures over the weekend will be in the 20s to high 30s F under partly cloudy skies with moderate southwest-west winds. There may be a sprinkling of snow tonight, but the next chance for real accumulation is towards the middle or end of next week.
Gusty westerly winds drifted this week’s new snow into cohesive slabs which are ready to avalanche. Yesterday, the Big Sky Resort Ski Patrol triggered wind slab avalanches up to 1 ft deep below alpine ridgelines with explosives during avalanche mitigation work. Steep slopes with fresh drifts of new snow in the backcountry have the same recipe and should be treated with caution. Unfortunately, these drifted areas also have the best coverage for skiing or riding. Don’t get lulled into poor decisions while trying to avoid rocks. If there is enough snow that you’re considering riding the slope on skis or with your snowmobile, there is enough snow to avalanche. Carefully consider and evaluate both the snowpack and the consequences of triggering an avalanche before riding steep slopes. The many rocks, cliffs and trees that are still exposed provide additional hazards that amplify the consequences of even a small slide.
Some slopes hold snow from October and early November with weak layers that can break in deeper avalanches. Any slope that held snow before this last storm should be suspect. Alex found these weak layers near Cooke City last week (video) and skiers near Fairy Lake reported similar layers (photo). Expect to find these weak layers at higher elevations across the advisory area.
The snow that is on the ground now is the foundation for the whole season’s snowpack. We still have limited information on the developing snowpack and would deeply appreciate hearing what you’re finding while you’re out in the mountains (submit observations here).
We are preparing for winter, teaching avalanche classes, and setting up weather stations. If you have avalanche, snowpack or weather observations to share please submit them via our website, email (firstname.lastname@example.org), phone (406-587-6984), or Instagram (#gnfacobs).
Upcoming Education Opportunities:
Get your avalanche brain ready for the season at one of the many classes listed on our education calendar, and list of upcoming events below. Don’t delay preparing and inspecting your avalanche gear. Get some tips from Dave Zinn in this Pre-Season gear check video.
November 30, 7-8 pm, Online Free 1 hr Avalanche Awareness in partnership with The Yellowstone Club Community Foundation. Link to Join Here.
December 1, 6-8 pm, Avalanche Awareness and Beacons at Beall Park. More info on our education calendar.
Our popular Avalanche Fundamentals with Field Course is perfect as a refresher or an introduction to avalanches. We are introducing an exciting new format this year with the four lectures pre-recorded to watch at your convenience, a live question and answer session, and a choice of a snowmobile or ski/ board based field day occurring the following three weekends.
Friends of GNFAC Powder Blast Fund-raiser
The Friends of the Avalanche Center are hosting the Virtual Powder Blast fundraiser. With only $4,000 left to go, help us reach the $65,000 goal. Your donations support free and low-cost avalanche education, beacon checkers at trailheads, beacon parks, weather stations, and GNFAC programs!
Doug was interviewed by Justin Angle for Montana Public Radio about his background, avalanches, and his work in Central Asia. You can listen to the interview HERE.