GNFAC Avalanche Forecast for Sun Dec 31, 2023

Not the Current Forecast

Good morning. This is Alex Marienthal with the Gallatin National Forest Avalanche Forecast on Sunday, December 31st at 6:00 a.m. This information is sponsored by Uphill Pursuits and Mystery Ranch. This forecast does not apply to operating ski areas.

Mountain Weather

This morning there is no new snow, temperatures are 20s to low-30s F, and wind is out of the southwest at 5-25 mph with gusts of 10-35 mph. Today, temperatures will reach high 20s to mid-30s F, and wind will be out of the west-southwest at 5-15 mph. No snow is expected until next year, but fingers are crossed for a storm in the forecast next weekend to bring some decent accumulation.

Snowpack and Avalanche Discussion

All Regions

The snowpack is shallow with an abundance of weak, sugary snow on most slopes. Ian and Doug discuss this in their video from Taylor Fork last week. A person can trigger an avalanche where the weak snow is capped with a supportable, cohesive slab. Slopes with this poor snow structure are mostly confined to where last week’s strong winds drifted snow into thicker slabs, or where more snow accumulated with the most recent storm over a week ago. 

On Thursday in the Bridger Range, Dave and Ian saw an avalanche that broke earlier in the week on a wind-loaded slope (video, photo). Over the last two days, skiers reported collapsing of the snowpack in Hyalite (observation 1, observation 2), Beehive (observation) and near Cooke City (observation), a sign of poor snow structure and the potential to trigger an avalanche on steeper slopes. The likelihood of triggering an avalanche has decreased as each day passes without snow, but large slides remain possible in specific areas.

Before riding or crossing steep slopes assess the snowpack for instability. If you find a stiff slab of snow that supports you on a sled or skis, stop to look for weak snow underneath. Avoid steep terrain where you find this poor snow structure, or if you see obvious signs of instability like collapsing and cracking. The thin snowpack requires only a few minutes to dig and do a stability test before getting into avalanche terrain. 

Human-triggered avalanches are possible and 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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