GNFAC Avalanche Forecast for Fri Dec 29, 2023

Not the Current Forecast

Good morning. This is Ian Hoyer with the Gallatin National Forest Avalanche Forecast on Friday, December 29th at 7:00 a.m. This information is sponsored by Alpine Yamaha in Livingston and Yellowstone Club Community Foundation. This forecast does not apply to operating ski areas.

Mountain Weather

Temperatures this morning are in the teens and 20s F with a slight inversion. Winds are 5-15 mph with gusts of 15-25 mph out of the south and west. There is no new snow. Any clouds this morning will quickly dissipate, becoming mostly sunny by the afternoon. High temperatures will be in the high 20s and 30s F. Winds will remain light and southwesterly. No new snow is expected through the weekend.

Snowpack and Avalanche Discussion

All Regions

Each day without new snow means you’re a little less likely to trigger an avalanche, but it remains very possible to trigger a dangerous slide.

Weak snow is widespread. Essentially every slope in our advisory area has it at this point after weeks or months of thin snowcover sitting and weakening. The missing ingredient for an avalanche on some slopes is a cohesive slab of snow on top. Yesterday, Dave and I saw an avalanche that broke on a windloaded slope in the Bridgers earlier in the week during a strong wind event (video). On this slope it was recent wind loading that built the slab, on others it may be older windloading or just a place where it snowed more earlier in the month. Pay close attention to the upper snowpack as you travel through the mountains. If you find a stiff slab of snow that is supporting you on a sled or skis, stop to investigate the stability. With the thin snowpack it’ll only take a few minutes to dig and do a stability test before getting into avalanche terrain. Also be alert for collapsing or cracking and be ready to back off steep slopes if you see these clear signs of instability.

Mountain temperatures will rise above freezing in many places today and the snow surface may get damp, but with the weak December sun wet avalanches are not a significant concern. 

The avalanche danger is MODERATE in the mountains around Bozeman, Big Sky, West Yellowstone, Island Park and Cooke City.

If you venture out, please fill an observation form. It does not need to be technical. Did you see any avalanches? How much snow is on the ground? Was the wind moving snow? Simple observations are incredibly valuable. You can also contact us via 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.

Every weekend in Cooke City: Friday at The Antlers at 7 p.m., Free Avalanche Awareness and Current Conditions talk, and Saturday from 10 a.m.-2 p.m. at Round Lake Warming Hut, Free Rescue Practice.

We offer Avalanche Fundamentals with Field Session courses targeted towards non-motorized travelers in January and one geared towards motorized users. Sign up early before they fill up.

King & Queen 2024, 3 February 2024. Form a team or sign up individually to hike laps on the Bridger Bowl ridge to fundraise for the Friends of the Avalanche Center. 

Loss in the Outdoors is a support group for those affected by loss and grief related to outdoor pursuits. Check out the link for more information.

The Last Word

Here’s a quick read, The Invisible Hands of Avalanche Work, an interview with GNFAC forecaster, Doug Chabot.

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