GNFAC Avalanche Forecast for Fri Nov 27, 2020

Not the Current Forecast

Good Morning. This is Alex Marienthal with pre-season avalanche, weather and event information for the Gallatin National Forest Avalanche Center on Friday, November 27th at 7:30 a.m. This information is sponsored by Cooke City Super 8/Bearclaw Bob’s and Mystery Ranch. We will issue our next bulletin when conditions change.

*Note: Bridger Bowl Ski Area is closed and there is no avalanche control or ski patrol services. Backcountry conditions exist. Workers are setting up for the season and making snow. Please stay clear of work areas, snow guns, chair lifts and other equipment.

Mountain Weather

Since yesterday morning the mountains got a trace to 1” of snow. Wind has been west-southwest at 15-25 mph with gusts to 30 mph, and gusts of 40-55 mph in the Bridger Range. This morning temperatures are teens to 20s F. Today, temperatures will be high 20s to low 30s F under partly cloudy skies with wind out of the west-northwest at 15-25 mph.

There is a slight chance for a trace of snow Monday night. Otherwise, skies will be mostly clear through the next week with daily temperatures reaching high 20s to low 30s F, and overnight lows in the single digits to teens F.

Snowpack and Avalanche Discussion

All Regions

Today and this weekend the main avalanche concern is fresh drifts of snow. Be cautious of slopes where yesterday’s snow was drifted into thick, dense slabs. I expect this problem is most widespread in the Bridger Range, where continuous strong winds over the last 24 hours have formed wind slabs along ridgelines and downwind of trees and convex slopes at all elevations.

The best strategy is to avoid steep wind loaded slopes for a day or two, and then carefully assess them after that. Keep in mind, the most dangerous slopes are where these slabs formed over weak, sugary snow. These slabs on top of sugar will be unstable for longer and can be less predictable, large and very dangerous.

On Tuesday, Dave and I found widespread weak, sugary snow near Lionhead (video) while Doug and Ian found generally stable snow in Cooke City (video). Climbers in Hyalite also found weak, faceted snow in many gullies.

During the next week of sunny weather, before riding steeper terrain look for the persistent weak layer problem by digging down to look at the layers of the snowpack. In some places finding sugary, persistent weak layers is as easy as looking in the track from your snowmobile, or poking through the snow with your hand or ski pole. If that doesn’t show a poor snowpack structure, get out your shovel and do a quick stability test to be sure. Avoid steep slopes where you find soft, sugary snow under a cohesive, supportable slab.

Every day we will update the weather log, photos page and avalanche activity list.  We will continue issuing early season updates and transition to daily avalanche forecasts when we get more snow. 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

See our education calendar for an up to date list of all local classes. Here are a few select upcoming events and opportunities to check out:

Every Saturday in Cooke City, FREE snowpack update and rescue practice at the Round Lake Warming Hut between 10am and 3pm. Starts this Saturday, November 28. Poster with More Info.

Monday, November 30, 6-7pm, FREE online 1-hr Avalanche Awareness, sponsored by Spark R&D. Join HERE.

December 7-8: Intro to Avalanches w/ Field in West Yellowstone. The 7th is online lectures from 1-5 p.m. and separate snowmobile and ski field days on the 8th. Info and sign up is HERE.

The December Avalanche Fundamentals with Field Course has SOLD OUT, but there will be a second course on January 23 and 24. There are separate field sessions tailored for both skiers and splitboarders (Bridger Bowl) and snowmobilers (Buck Ridge).

Doug spoke with the Last Best Ski Podcast about avalanche fundamentals, some climbing history, and the workings of the GNFAC. The 25-minute podcast is available here.

Support the Friends of the GNFAC

This year, The Friends of the Avalanche Center are unable to host an in-person Powder Blast due to COVID. In place of their biggest fund-raiser, the Friends of GNFAC launched an online GoFundMe campaign. Please consider a donation, and we look forward to having an in-person event again in the future.

The Last Word

The Friends of the Avalanche Center are encouraging everyone to take an avalanche class. Look at our Education Page for all the classes being offered in sw Montana. They are working hard to break down Backcountry Barriers and made this awesome 6 min video about it.

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