GNFAC Avalanche Forecast for Sat Dec 14, 2019

Not the Current Forecast

Good Morning. This is Ian Hoyer with the Gallatin National Forest Avalanche Forecast on Saturday, December 14th at 7:00 a.m. Today’s forecast is sponsored by Beartooth Powder Guides and Swiss Fit Montana. This forecast does not apply to operating ski areas.

Mountain Weather

There is only a trace to an inch of new snow this morning. Winds are westerly at 5-15 mph. Temperatures are in the single digits to high teens F. Several pulses of light snowfall today and tonight will drop an inch or 2 around West Yellowstone and Cooke City, and 2-4” near Bozeman and Big Sky. Temperatures will rise to the high teens to low-20s F. Winds will be 10-20 mph out of the west and northwest under cloudy skies.

Snowpack and Avalanche Discussion

Yesterday, in Taylor Fork, Alex found challenging riding conditions with a foot of newer snow over very weak snow at the base of the snowpack. He got unstable test results and saw a recent avalanche that broke 1000 ft wide (video). I found similar conditions on Thursday at Buck Ridge (video) as did Dave earlier in the week at Lionhead (video). The exact composition of the weak layers varies a little, but the overarching story is the same – multiple layers of weak snow are capped by a foot or more snow that fell over the last week. This is an unstable recipe. You can trigger avalanches remotely from below or from adjacent low angle terrain. With CONSIDERABLE avalanche danger today, avoid riding on or below steep slopes.

In Cooke City yesterday, riders remotely triggered a large avalanche from the flats below a steep slope (details). It broke 2 ft deep, likely on the weak layer of facets mid-pack (video, photo). Recent avalanches are the clearest sign of instability. The potential to remotely trigger a slide means you need to give yourself an extra large safety margin. Give steep slopes a wide berth today. The avalanche danger is CONSIDERABLE.

In the Bridger Range, there is a weak layer of faceted snow buried around a foot deep. We haven’t seen much activity on this layer recently, but it still merits caution, especially on slopes where it is buried deeper and capped by a hard windslab (video). Yesterday, skiers in the northern Bridgers were surprised by an unstable test result on this layer. Triggering a large avalanche is possible and the avalanche danger is rated MODERATE.

Avalanche concerns in the northern Gallatin Range are limited to windloaded slopes (video). Skiers on Blackmore yesterday got a very unstable test result (ECTP8) under the new snow on a windloaded slope and chose to play it safe by skiing back down their skin track. Search for signs of instability (particularly cracking wind slabs and unstable test results) and dial back your terrain choices if you find it. The avalanche danger is MODERATE on wind-loaded slopes and LOW on all other slopes.

If you get out, please send us your observations no matter how brief. You can fill out an observation form, email us (mtavalanche@gmail.com), leave a VM at 406-587-6984, or Instagram (#gnfacobs).


Island Park

We are not issuing danger ratings.
Multiple layers of weak snow are capped by a foot or more snow that fell over the last week. This is an unstable recipe. You can trigger avalanches remotely from below or from adjacent low angle terrain. Avoid riding on or below steep slopes.

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.

BOZEMAN

December 18, 1-hr Avalanche Awareness, 6-7 p.m. at Uphill Pursuits.

COOKE CITY

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.

BILLINGS

December 17, 1-hr Avalanche Awareness, 6-7 p.m. Elevated Powersports.

CHOTEAU

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

The Last Word

Check out this report of a close call with an avalanche in Alaska. A solo hiker was caught and buried for over an hour before being dug out by a passer-by. While we're glad it had a happy outcome, it’s a good reminder to always carry rescue gear and go with a partner to tilt the odds in your favor.

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