Good Morning. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Friday, December 1st at 7:00 a.m. Today’s advisory is sponsored by Gallatin County Search and Rescue and Edward Jones in partnership with the Friends of the Avalanche Center. This advisory does not apply to operating ski areas.
NEW THIS SEASON: Regional Conditions Pages. Links at top of advisory and in the ‘advisory’ dropdown menu.
Overnight 1-2” of snow fell in the mountains around West Yellowstone and Cooke City. The mountains around Bozeman and Big Sky remained dry. This morning temps range from the upper teens to mid-20’s F under partly cloudy skies and winds are blowing 10-25 mph out of the west. Today, skies will gradually clear and temperatures will warm into the upper 20’s F. Winds will increase slightly as the progresses with ridgetop gusts reaching close to 30 mph by this afternoon. There is little chance for precipitation over the next 24 hours, but the mountains will see an increased chance of light snow showers tomorrow.
Stability is generally good across the advisory area. There is little in the way of buried persistent weak layers and the snowpack has not endured significant loading over the past few days (video). The biggest avalanche concern today is wind drifted snow near the ridgelines. Steady west winds throughout the week have formed drifts 1-2’ thick on leeward slopes (photo, photo). These drifts shouldn’t be overly sensitive to human triggers, but I still wouldn’t trust them, especially in steeper high consequence terrain. It should be easy to recognize and avoid wind loaded slopes today, which will be the best way to avoid triggering a slide.
Although we have the pleasure of enjoying a mostly stable snowpack, a massive avalanche at Big Sky Ski Resort yesterday highlights the fact that not all is perfect (video, facets photo). This slide occurred on the North Summit Snowfield during control work and created a crown up to 10’ feet deep. It failed on depth hoar that formed from the snow that fell in September. The slide broke 500 vertical feet above the shot that triggered it producing an impressive display of propagation. This avalanche ran full path and broke mature trees in the run out zone. While this slide isn’t highly representative of the overall snowpack, it’s a good reminder of what remains possible.
Today, human triggered avalanches are possible on wind loaded slopes which have a MODERATE avalanche danger. Non-wind loaded slopes have a LOW avalanched danger.
If you get out and have any avalanche or snowpack observations to share, drop a line via our website, email (mtavalanche@gmail.com), phone (406-587-6984), or Instagram (#gnfacobs).
Get Avalanche Smart Video Series
The Avalanche Center and Friends group work hand-in-hand to bring you daily avalanche information and education. This last video in series of 4 shows how we create a culture of being safe in the backcountry: Get Avalanche Smart – Episode 4: The GNFAC
Upcoming Avalanche Education and Events
BOZEMAN
Dec. 6, Avalanche Awareness, 6-7:30 p.m. at REI Bozeman
Dec. 7, Avalanche Awareness and Beacon Practice, 6-8 p.m. at Beall Park, Bozeman
Dec. 13, Avalanche Awareness, 6:30-8 p.m. at Gallatin Valley Snowmobile Association, 4-Corners
Jan. 12 and 13, Companion Rescue Clinic, Info and Register
Jan. 17, 18 and 20 or 21, Introduction to Avalanches w/ Field Day, Info and Register Here
Jan. 24, 25 and 27, Advanced Avalanche Workshop w. Field Day, Info and Register Here
Feb. 9 and 10, Companion Rescue Clinic, Info and Register
HELENA
7 December, Avalanche Awareness, 6-7:30 p.m. at Basecamp, Helena
WEST YELLOWSTONE
Dec. 14 and 15, Snowmobiler Introduction to Avalanches with Field Course, Info and Register Here
COOKE CITY
1 and 2 December, Current Conditions and Avalanche Rescue, 6:30-7:30 p.m. Friday @ the Super 8, and anytime between 10-2 on Saturday 2 Lulu Pass road.
Check out our playlist of videos from last April’s Professional Development Workshop. The topic of the day was “Avalanche Science, Avalanche Stories”.