GNFAC Avalanche Forecast for Thu Dec 19, 2019

Not the Current Forecast

Good Morning. This is Doug Chabot with the Gallatin National Forest Avalanche Forecast on Thursday, December 19th at 7:00 a.m. Today’s forecast is sponsored by Your Montana Chevy Dealers and Cooke City Super 8/Bearclaw Bob’s. This forecast does not apply to operating ski areas.

Mountain Weather

At 5 a.m. there’s no new snow, just strong southwest wind gusting to 45 mph and temperatures in the mid-teens F. Today will remain windy and become cloudy as temperatures rise into the high 20s F. Tonight 1-2” will fall around West Yellowstone and Cooke City with a dusting everywhere else.

Snowpack and Avalanche Discussion

In the mountains around Big Sky to West Yellowstone the snowpack is weak. Sugary snow near the ground continues to show signs of instability. Karl and I rode into Lionhead on Tuesday and got large collapses on this layer. The snowpack was less than 3 feet deep and audibly “whumphed” under our body weight. Alex found similar structure in Taylor Fork (video) and riders reported avalanches over the weekend (details). Dave had these facets break in stability tests during an avalanche class on Buck Ridge (video) and heard a third hand account of riders tiggering avalanches nearby slopes. Yesterday, the Big Sky Ski Patrol triggered an avalanche with explosives on this weak layer. Almost daily signs of instability and poor stability test scores can only be interpreted one way: avalanches are still possible and getting onto steep terrain requires a serious assessment. For today, the avalanche danger is rated MODERATE.

The mountains around Cooke City have not gotten snow in the last six days and avalanche activity has subsided since the weekend. There is still weakness lingering in the snowpack: weak snow (facets) on an ice crust is buried 2-3 feet deep on many slopes, seemingly south to east facing. On Monday, Ian and I investigated a large slide on Mt. Abundance that was triggered by a sledder who was unharmed, unlike his totaled sled (photos and details, video). We posted photos of many avalanches that occurred on Saturday, December 14. These slides on Mt. Fox, Republic Creek, the Fin and Crown Butte are reminders to not be complacent. Although slopes have become less sensitive to triggering, avalanches are still possible. Popular riding spots like the south face of Scotch Bonnet and south face of Mt. Abundance have this weak layer and are suspect. For today, the avalanche danger is MODERATE. Ride and ski with partners, watch each other, only go one at a time on steep slopes and carry rescue gear. And this advice goes for Bison too!

In the Bridger and northern Gallatin Ranges the snowpack is generally stable. Yesterday, Ian skied into Divide Peak and found stable and similar conditions to Dave’s trip to Mt. Blackmore (video). West to southwest wind has been blowing strong all week and drifting snow. During the day and evening on Tuesday natural avalanches released in the wind-drifted snow. A few smaller slides in Hyalite pulled off the ridgeline (details) and a much larger slide broke in wind-loaded terrain on Saddle Peak (details). There are still isolated pockets of windblown snow that could be triggered and it is worth doing a quick stability test before getting into avalanche terrain. For today, the avalanche danger is rated LOW.

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.


TONIGHT! December 19, 1-hr Avalanche Awareness, 7-8 p.m. at Choteau High School.

The Last Word

On Monday, when I was in Cooke City with Ian, I forgot to bring the handle to my shovel! Duh! While packing I got distracted. I felt like a dufus. We avoided avalanche terrain and as a precaution I carried Ian’s shovel so he would not pay the price of my forgetfulness.

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