GNFAC Avalanche Forecast for Thu Dec 6, 2018

Not the Current Forecast

Good Morning. This is Eric Knoff with the Gallatin National Forest Avalanche Forecast issued on Thursday, December 6th at 6:45 a.m. This forecast is sponsored by Cooke City Motorsports and Gallatin Valley Snowmobile Assoc., and does not apply to operating ski areas.

Mountain Weather

This morning temps range from the single digits above or below zero F under clear skies. Winds are blowing 10-20 mph out of the west-southwest. Skies will remain clear today and temps will warm into the teens F. Winds will blow 10-20 out of the west, but shift to the northwest this afternoon. No new snow is expected through the weekend.

Snowpack and Avalanche Discussion

All Regions

It doesn’t need to be snowing for the avalanche danger to increase. On Tuesday, skies were clear but strong winds combined with abundant low-density snow formed sensitive wind slabs on all aspects and elevations. These slabs failed naturally and with human triggers. Fortunately, all activity stayed confined to new snow and didn’t step into layers deeper in the pack. Visit our photo and video pages for a more comprehensive look at recent events.

Yesterday, winds decreased but avalanches still occurred. The Big Sky Ski Patrol triggered wind slabs during control work and a skier near Imp Peak in the southern Madison Range also triggered a small wind slab (photo). These are good reminders that wind loaded slopes still hold the potential to fail under the weight of a skier or rider. Today, watch for and avoid rounded pillows of wind drifted snow and always be thinking about the consequences of a slide. Slopes with terrain traps such as gullies, cliff bands or dense trees will amplify the consequences of being caught. Extra caution is advised for all ice climbers attending the Bozeman Ice Festival. The steep gullies up Hyalite need to be traveled with caution.

Today, human triggered avalanches are possible on wind loaded slopes which have a MODERATE avalanche danger. Non-wind loaded slopes have a LOW avalanche danger.   

I will issue the next advisory tomorrow morning by 7:30 a.m. If you get out and have any avalanche or snowpack observations to share, contact us via our website, email (, phone (406-587-6984), or Instagram (#gnfacobs).

Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar.


Tonight, December 6, 1-hr Avalanche Awareness and Beacon Practice, 6:30-8 p.m. at Story Mill Park.

December 7 and 9, Beacon Park for the Bozeman Ice Fest, Grotto Falls parking lot, Hyalite Canyon, 10 a.m. to 2 p.m.

December 11 and 12, Snowmobile Intro to Avalanches w/Field, Holiday Inn, West Yellowstone; more info here.

December 12, 1-hr Avalanche Awareness for Snowmobilers, 6-7 p.m. at Yellowstone Motorsports, Bozeman.

December 13, 1-hr Avalanche Awareness, 6-7 p.m. at Play It Again Sports, Bozeman.


December 12, 1-hr Avalanche Awareness, 6-7 p.m. at The Basecamp, Helena.


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

The Last Word

Check out our new “Avalanches and Snowpits” menu item where we list all the reported avalanche activity.

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