GNFAC Avalanche Forecast for Mon Feb 18, 2019

Not the Current Forecast

Good morning. This is Alex Marienthal with the Gallatin National Forest Avalanche Forecast issued on Monday, February 18th at 7:00 a.m. Today’s forecast is sponsored by Cooke City Super 8/Bearclaw Bob’s and Map Brewing. This forecast does not apply to operating ski areas.

Mountain Weather

Yesterday light snow dropped 1” near West Yellowstone and almost a trace elsewhere. Wind has been easterly at 0-10 mph. This morning temperatures are single digits below and above zero F. Today temperatures will reach single digits and low teens F, and wind will be 5-10 mph and shift west-southwest this afternoon. There is a chance for scattered light snow showers to drop a trace to 2” by tomorrow.

Snowpack and Avalanche Discussion

Over the weekend, light snowfall and minimal wind gave buried weak layers time to recover from the stress of last week’s 3-4’ of heavy snow (weather log). In the mountains near West Yellowstone and the southern Madison and Gallatin ranges it is possible to trigger avalanches that break on weak, sugary snow at the base of the snowpack (photo). These deep avalanches are becoming difficult to trigger, but the consequences are deadly. On Saturday, Eric rode in Taylor Fork and saw a cornice triggered avalanche that broke at the base of the snowpack and deposited debris 10’ deep (photo, video). Yesterday skiers near Bacon Rind saw recent large natural avalanches, similar to what is possible to trigger today (details). Wind loaded slopes are particularly dangerous. Cornices have grown large and could fall and trigger a big avalanche (photo). Today, avoid steep wind loaded slopes and be extra cautious of all steep slopes. Large avalanches are possible to trigger and avalanche danger is MODERATE.

In the mountains near Bozeman, Big Sky and Cooke City weak layers in the lower half of the snowpack are not as widespread, but exist on some slopes. Yesterday two avalanches were triggered by snowmobilers on Buck Ridge near Big Sky (details, details), and one was triggered on Crown Butte near Cooke City (details). All three were on wind loaded slopes and broke 3-4’ deep, likely on persistent weak layers. On Friday near Cooke City I saw an avalanche that was 4-8’ deep and triggered by a cornice fall on a heavily wind loaded slope (video, details). Some slopes are strong while others are weak. This is why we carefully assess each slope, carry rescue gear and only expose one person at a time. In case we get surprised.

Doug and Ian rode the entire area north of Cooke City yesterday and noted only one avalanche which broke in the new snow (details, video). Over the weekend similar slides were reported in Hyalite (details), Beehive (photo), the Bridger Range (photo, photo) and Cooke City (photo). Today these soft slabs of recent snow are possible to trigger on previously wind loaded slopes. Avoid steeper terrain if you see cracking in the snow surface, and dig 3-4’ to check for unstable weak layers. Avalanches of recently drifted snow are possible and can break deeper on specific slopes where buried weak layers exist. Avalanche danger is MODERATE on wind loaded slopes and LOW on non-wind loaded slopes.

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

Upcoming Avalanche Education and Events

Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar.


February 22 and 23, Women’s Companion Rescue Clinic, 6-8 p.m. Friday at REI, 10-4 Saturday in the field. More Info and Register.

March 1, 2 and 3, Bozeman Split Fest, More info at


February 23, 1-hr Avalanche Awareness for Snowmobilers, 7-8 p.m. Holiday Inn West Yellowstone.


Every Friday and Saturday, Rescue Training and Snowpack Update. Friday 6:30-7:30 p.m. at the Soda Butte Lodge. Saturday anytime between 10-2 @ Round Lake.

The Last Word

On Saturday near Crested Butte, Colorado two skiers were caught and killed in an avalanche. Preliminary details here. This is the 14th and 15th fatality in the U.S. this season.