GNFAC Avalanche Forecast for Mon Oct 21, 2019

Not the Current Forecast

This is Dave Zinn with pre-season avalanche, weather, and event information for the Gallatin National Forest Avalanche Center on Monday, October 21st. This information is sponsored by Grizzly Outfitters and Your Montana Chevy Dealers, both supporters of this week’s Powder Blast fundraiser.

Mountain Weather

Since our last early-season advisory on Thursday the Bridger and North Gallatin Ranges collected the most snow in our area with 21” falling in the Bridgers and 17” in Hyalite. The mountains around Big Sky picked up 14” with Cooke City and Lionhead getting 9.” Temperatures were in the high teens and 20s with winds from the West averaging 10-15 mph with gusts up to 45 mph on ridgetops. 

Snow showers will continue today and tonight with an additional 4-6” falling in the mountains around Bozeman and 2-4” around Big Sky, West Yellowstone, and Cooke City. Temperatures will be in the upper 20s with winds from the West at 10-20 mph. Another cold front will arrive on Tuesday evening with a chance for additional snow. 

We will update our Weather Log and Regional Conditions every morning with snowfall totals, and our Avalanche Activity list if we get a report. The Regional pages have webcams and links to weather stations.

Snowpack and Avalanche Discussion

All Regions

Winter enthusiasts got a treat this weekend with a serious shot of snow in our advisory area. While the Bridger Range came out on top with 21”, our entire forecast area received snow. This changes the avalanche equation. There is now fresh snow available for wind transport and the new snow is giving layers of old snow existing at the higher elevations their first stress test. While we appreciate and share your enthusiasm for winter, avalanches are indifferent. Ice climbers in Hyalite Canyon triggered a small, but potentially consequential avalanche on Sunday (Photo). Now is not the time to ruin your season or worse. 

Early season avalanches can punish anyone captured in them. 25% of avalanche victims die from trauma rather than asphyxiation. There is plenty of snow on the ground for an avalanche to drag you across rocks, into trees, and off cliffs. Always carry your avalanche rescue tools and practice safe travel with your partners.

We are collectively determining what the avalanche hazard will look like this season. New snow and wind increase the avalanche danger. We have had both over the weekend and we will have more in the next couple days. Be on the lookout for recent avalanche activity, collapsing, and cracking of the snowpack. All of these are highly specific indicators of instability. Take the time to dig a quick snowpit and perform a stability test. If you witness failure and propagation, look for lower angle terrain. 

We are preparing for winter, setting up weather stations and beginning to collect snowpack information. If you have avalanche, snowpack or weather observations to share, please submit them via our website, 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 and plan to attend one or two: Events and Education Calendar.

Get tickets for the 21st Annual Powder Blast Fundraiser on October 25th at The Emerson Ballroom.


6 November, 1-hr Avalanche Awareness, 6-7pm @ REI Bozeman.

7 November, 1-hr Avalanche Awareness, 6-7pm @ Langford Hall, MSU.

12 November, 1-hr Avalanche Awareness, 6-7pm @ Montana Ski Tuning and Boot Fitters.

14 November, 1-hr Avalanche Awareness, 6-7pm @ South Hedges Hall, MSU.

14 November, 1-hr Avalanche Awareness, 6-7pm @ Uphill Pursuits.

20 November, 1-hr Avalanche Awareness, 6-7pm @ The Mountain Project.

4 & 5 December, Introduction to Avalanche w/ Field Course, Evenings of December 4 & 5 plus one field day either December 7, 8 or 14. Snowmobile specific field day offered December 14. More info and Register Here.


6 November, 1-hr Avalanche Awareness, 6-7pm @ The Base Camp in Helena.


19 November, 1-hr Avalanche Awareness, 6-7pm @ The Base Camp in Billings.

The Last Word

Read accident reports from previous early season accidents before you venture to the snowy hills. This accident report from October 2012 in the northern Bridger Range, and this report from the tragic fatality two years ago in early October are reminders of the potential consequences of even a small avalanche.