GNFAC Avalanche Advisory for Mon Mar 12, 2018

Not the Current Advisory

Good Morning. This is Alex Marienthal with the Gallatin National Forest Avalanche Advisory issued on Monday, March 12th at 6:30 a.m. Today’s advisory is sponsored by Ph.D. Skis and Bridger Bowl. This advisory does not apply to operating ski areas.

Mountain Weather

This morning the mountains do not have any new snow, temperatures are high teens to 20s F and wind is south to westerly at 5-15 mph. Today will have clear skies with temperatures in the high 20s to high 30s F and light wind at 0-5 mph. The next chance for snow is late Wednesday.

Snowpack and Avalanche Discussion

The mountains near Cooke City received 7-10” of snow at the end of last week, which was drifted into wind slabs by strong southwest wind on Friday. On Saturday, a skier on the Fin triggered a 1-2’ deep wind slab and was partially buried (photo). They also reported another similar sized slide later in the day (photo). These 1-2’ thick drifts are possible to trigger on shady wind loaded slopes, where the snow surface is dry and did not form a crust from sun and warm temperatures yesterday (photo). Be cautious of wind loaded slopes and keep a far distance from the edge of large cornices and avoid slopes below. Avalanche danger today is MODERATE on wind loaded slopes and LOW otherwise.

In the mountains near Bozeman, Big Sky and West Yellowstone, warm weather and a lack of snow and wind allowed recent instabilities to gain strength and the snowpack is generally stable (video). Large cornices along ridgelines are the main avalanche concern (photo, photo). Cornices can break unexpectedly and farther back than anticipated. On Saturday, a cornice broke naturally and triggered an avalanche in the Hourglass chute north of Bridger Bowl (photo, photo). Keep a far distance back from the edge of ridgelines and avoid slopes directly below large cornices.

Avalanche danger today is LOW. This means small and isolated avalanches can be triggered (video). Last Wednesday, a snowmobiler triggered and escaped an avalanche in the southern Madison Range (video, accident report). The snowpack lacks widespread weak layers, but digging to assess structure and stability is recommended before riding in avalanche terrain.

WET AVALANCHES will be minimal today as surface crusts soften slowly, but can be triggered on steep, sunny slopes when crusts melt. They can occur naturally around rock outcrops and below cliffs. Be cautious of steep, sunny slopes if you see rollerballs or natural wet loose slides (photo, photo).

If you get out and have any avalanche or snowpack observations to share, drop a line via our website, email (, phone (406-587-6984), or Instagram (#gnfacobs).

Upcoming Avalanche Education and Events

Events and Education Calendar


March 20, Beer for a Cause Night at Katabatic Brewing, 4-8p.m. A dollar from every pint will be donated to The Friends of the Avalanche Center.

The Last Word

In the last 2 weeks there were 9 avalanche fatalities in the western U.S. Our snowpack is currently more stable than other areas, but now is no time to let your guard down. See info on recent accidents here: