Good Morning. This is Alex Marienthal with the Gallatin National Forest Avalanche Advisory issued on Monday, November 27th at 7:05 a.m. Today’s advisory is sponsored by Cooke City Super 8/Bearclaw Bob’s and Bountiful Table. 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 around 4 a.m. near West Yellowstone, Big Sky, and the Gallatin Range. Temperatures this morning are low 30s F and wind is southwest at 20-30 mph with gusts of 40-60 mph. A cold front passing this morning will bring temperatures in the 20s F today and low teens tonight. Wind will shift to the west-northwest at 15-20 mph, and snowfall this morning will total 3-6” with up to 8” possible near Big Sky, Hyalite, and Cooke City.
Snowpack depth decreased last week with above freezing temperatures, yet the mountains still hold 2-3 feet of dense, settled snow with up to 6 feet near Cooke City. Fresh snow today will be a welcome improvement to riding and skiing conditions, and the snowpack is mostly stable aside from instability associated with new snow today (video).
Fresh drifts of snow will form near ridgelines and be easy to trigger as they grow today. The size and distribution of these wind slabs will depend on the amount of snow and wind this morning. This instability will likely be short lived, and is easiest to avoid with careful terrain selection for a couple days. Plan to avoid fresh drifts along ridgelines and keep an eye out for unstable drifts along the edge of gullies or the base of cliffs.
Steady snowfall and relatively warm temperatures through October and mid-November created a strong snowpack without widespread weak layers. New snow amounts today near the hopeful forecast of 8-15” will probably not be enough to trigger avalanches deeper than the new snow. However, more new snow creates more instability. Avoid avalanche terrain if you see obvious signs of instability such as cracking and collapsing or natural avalanches. Dig down a foot or two to assess the interface between the new snow and old snow; and look a couple feet below the new snow for isolated deeper instabilities, similar to the unstable results in this snowpit or this avalanche last week near Cooke City (photo).
New snow this morning makes avalanches possible today and the avalanche danger is MODERATE.
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. 28, Avalanche Awareness, 6-7:30 p.m. at Play it Again Sports
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.