GNFAC Avalanche Forecast for Fri Jan 17, 2020

Not the Current Forecast

Good Morning. This is Ian Hoyer with the Gallatin National Forest Avalanche Forecast on Friday, January 17th at 7:00 a.m. Today’s forecast is sponsored by Cooke City Motorsports and Yellowstone Club Community Foundation. This forecast does not apply to operating ski areas.

Mountain Weather

At 6 a.m. there is no new snow. Southerly winds are 10-25 mph with gusts of 30-45 mph and up to 60 mph in Hyalite. Winds will shift more westerly today and blow 20-35 mph. Temperatures are high teens to mid-20s and will stay fairly steady through the day. A quick moving storm this morning will drop 2-4 inches by early afternoon. A second pulse tonight will bring a few more inches to the mountains around West Yellowstone and Cooke City.

Snowpack and Avalanche Discussion

Yesterday, snowmobilers triggered two large avalanches on Henderson Mountain near Cooke City. One of these slides was absolutely huge, breaking more than 10 feet deep in spots (photo). A large natural avalanche also broke yesterday near Hardscrabble Peak in the northern Bridger Range (photo). It initially failed 2-3 ft deep and then stepped down to the ground.

Conditions aren’t hair trigger today. It’s been 48 hours since the last snowfall. While winds have continued to load some slopes, most slopes are handling the load well. However, as yesterday’s slides demonstrate, triggering a large avalanche is a very real possibility today that could have devastating consequences.

Figuring out whether a particular slope is primed to slide is going to be a real challenge and in some cases near impossible to do safely. Tracks are not a guarantee of stability. Wednesday’s sobering close call with a large skier triggered slide on Saddle Peak is a good reminder of this (details). A number of skiers had skied the very similar adjacent slopes without incident before one got unlikely, hit the wrong spot, and triggered a big avalanche.

Remember the big picture: many slopes have weak layers low in the snowpack and multiple large avalanches have been triggered on those layers each of the last three days (see the avalanche activity page for a list of reported slides). Think long and hard before getting into avalanche terrain today. Be extra skeptical of slopes that have recently been windloaded or are getting activity loaded today.

Human triggered avalanches are possible and the avalanche danger is MODERATE today.

The snowpack is generally stable in the northern Gallatin Range with the exception of wind-drifted slopes. Strong winds have continued in Hyalite (gusts up to 60 mph overnight) but there is no more loose snow left to transport. While at this point most drifts will be well bonded, watch for shooting cracks as your sign you’ve found one that hasn’t yet. Avoid those slopes. For today, the danger is MODERATE on windloaded slopes and LOW on all others.

If you get out, please send us your observations no matter how brief. You can fill out an observation form, email us (, leave a VM at 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 and plan to attend one or two: Events and Education Calendar.


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


January 27, Avalanche Information and Demonstration Table, 10 a.m. to 12 p.m. at Montana Science Center.

January 29, GNFAC Forecaster Chat: Avalanche Myth Busters, 6-8 p.m. at Uphill Pursuits.

January 31, Women’s Only Companion Rescue Clinic, 6 - 8 pm at REI followed by a field day February 1. More info and Register Here.

February 1, King and Queen of the Ridge at Bridger Bowl (fundraiser). This is the Friends of the Avalanche Center’s second biggest fundraiser of the year. Come on out and help us raise money by hiking and skiing laps on the ridge. Prizes, camaraderie and a good time is guaranteed. Register with Bridger to hike in the event, and create a pledge page to raise funds with your Ridge laps.


January 29 and 30, Introduction to Avalanche w/ Field Course, evenings of January 29 & 30 plus a field day February 1. Snowmobile specific field day offered February 2. More Info and Register Here.


TOMORROW! January 18, 1-hr Avalanche Awareness, 10 a.m. to 12 p.m. at Homestake Lodge.


January 25, 1-hr Avalanche Awareness, 7-8 p.m. at West Yellowstone Holiday Inn.

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


January 28, 1-hr Avalanche Awareness, 6-7 p.m. Carroll College.


January 30, Introduction to Avalanche w/ Field Course, evening of January 30 plus a field day February 2. More info and Register Here.

The Last Word

A snowmobiler was killed in an avalanche in Idaho on Wednesday, Jan 15. A video with preliminary info from the Sawtooth Avalanche Center is here.

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