Good Morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Tuesday, November 28th at 6:45 a.m. Today’s advisory is sponsored by Spark R&D and World Boards. 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.
Snowfall started at 4 a.m. yesterday morning and ended by noon, dropping 3” in the Bridger Range and 6-8” everywhere else. Westerly winds averaged 15-25 mph with gusts of 45 last night. Under clear skies temperatures fell to 10F in the mountains. Today will be sunny and temperatures will rise into the high 20s with W-SW winds averaging 15-25 mph. After midnight the mountains may get 1-2” of snow from a quick storm.
The weather this last week has given us a good whiplashing: snow, then rain, then shorts and sunscreen, then more rain, then snow yesterday morning. This has played havoc on the skiing and riding conditions, but as an avalanche forecaster I’m smiling because this wacky weather helped create a generally stable snowpack. There’s a lack of widespread weak layers and the temperature swings and rain helped densify and strengthen the snow. The mountains have 2-3’ of dense snow with close to 6’ outside Cooke City. Yesterday, Eric found soggy snow below 9,000’ in the Bridger Range and skiers reported similar mushiness at low elevations in Beehive Basin and Cook City. This will freeze in the next few days and strengthen the snowpack even further.
Yesterday’s new snow was blown by westerly winds (photo) forming wind slabs near the ridgelines. Skiers on Mt. Blackmore got a few drifts to crack while the Big Sky Ski Patrol reported wind-loaded slopes stubborn to avalanche. This new snow fell onto a variety of surfaces ranging from an ice crust to moist snow. In most instances it bonded to the old surface, but dig 1-2’ deep to this interface to confirm the stability before exposing yourself to avalanche terrain.
Moist snow at lower elevations and wind-loading up high point to the possibility of human triggered slides. For today, the avalanche danger is MODERATE.
Our forecasting season has just begun and we are being conservative with our assessments as we gather more snowpack information. I am pretty happy that the snowpack does not have widespread weak layers, but there are a few slopes that could surprise us. A snowpit showing instability and a small wet slab (photo) outside Cooke City last week are both reminders to not let our guard down.
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
Some days the big lines will go, but other days they won't. It's up to you to decide, because the best days are the ones when you return home safely. Three skiers walk through the decision making process in Get Avalanche Smart - Episode 3: The Great One.
Upcoming Avalanche Education and Events
BOZEMAN
Nov. 29, 30 and Dec. 2, 3 or 9, Introduction to Avalanches w/ Field Day, Info and Register Here
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”.