GNFAC Avalanche Forecast for Sat Dec 30, 2023

Not the Current Forecast

Good morning. This is Alex Marienthal with the Gallatin National Forest Avalanche Forecast on Saturday, December 30th at 7:00 a.m. This information is sponsored by Stronghold FabricationCooke City Motorsports and Bridger Bowl. This forecast does not apply to operating ski areas.

Mountain Weather

This morning there is no new snow, temperatures are mid-20s to mid-30s F, and wind is out of the southwest-west at 5-15 mph with gusts of 10-25 mph. Today, temperatures will reach mid to high 30s F, and wind will be out of the south-west at 5-15 mph. No snow is expected until later next week.

Snowpack and Avalanche Discussion

All Regions

Avalanches are possible to trigger where supportable slabs of snow sit over weak snow. Weak snow is widespread and exists on most slopes. However, the last six days without new snow has led to fewer slopes with an unstable layering of cohesive slabs on top of weak snow. Before riding or crossing steep slopes assess the snowpack for instability. Avoid steep slopes if you find a poor snow structure or see obvious signs of instability like collapsing and cracking. With the thin snowpack it’ll only take a few minutes to dig and do a stability test before getting into avalanche terrain. If you find a stiff slab of snow that supports you on a sled or skis, stop to look for weak snow underneath and avoid steep terrain where you find this poor snow structure.

The most suspect slopes are where strong winds drifted last week’s snow into thicker slabs or where more snow accumulated last week. A couple days ago in the Bridger Range, Dave and Ian saw an avalanche that broke earlier in the week on a wind-loaded slope (video, photo). Yesterday skiers reported collapsing of the snowpack in Hyalite (observation), Beehive (observation) and near Cooke City (observation), a sign of poor snow structure and the potential to trigger an avalanche on steeper slopes.

Today mountain temperatures will rise above freezing in many places, and wet avalanches may be possible on steep slopes that heat up in the sun. Watch for roller balls as a sign the snow surface is becoming damp and unstable.

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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