GNFAC Avalanche Advisory for Tue Mar 12, 2013

Not the Current Forecast

Good morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Tuesday, March 12 at 7:30 a.m. Montana Import Group in partnership with the Friends of the Avalanche Center sponsor today’s advisory. This advisory does not apply to operating ski areas.

Mountain Weather

This morning there is no new snow to report. Mountain temperatures are in the low teens under partly cloudy skies. West winds have decreased from 20-40 mph to 15-20 mph. Clouds will build throughout the day as temperatures rise into the upper 20s and winds remain the same. The southern mountains may get a few flurries later today, but accumulations should be less than an inch.

Snowpack and Avalanche Discussion

Bridger Range   Madison Range   Gallatin Range   

Lionhead area near West Yellowstone   Cooke City

Yesterday’s strong winds scoured high elevation terrain with a few slopes getting loaded and forming stubborn wind drifts.  Mark found shallow wind slabs outside Cooke City this weekend (photo) and kicked off a small 8” pocket yesterday. I toured north of Bridger Bowl into the Hourglass Chute on Sunday and found stable conditions, but I also avoided the smooth wind-whale of drifted snow on the northern entrance. That same day in the Bridger Range, a skier in Naya Nuki Bowl was caught in a small avalanche when he triggered a wind-loaded pocket under some cliffs (photo). Although small, these types of slides can be deadly if they push you into terrain traps.

A persistent weak layer of facets buried 2-3 feet deep (video) is slowly getting stronger and becoming harder to fracture in our stability tests. We still need to keep an eye on it, especially if the snowpack is thin and sugary. Riders in Taylor Fork backed off a steep slope on Sunday when they noticed their tracks were chewing through sugary, faceted snow at the ground. These thinner, weaker spots are where avalanches can be triggered.

Overall the stability is good, but not perfect. For today, the avalanche danger is rated MODERATE on all wind-loaded slopes. On slopes lacking a wind-load, the danger is MODERATE if it is steeper than 35 degrees and LOW on less steep terrain.

I will issue the next advisory tomorrow morning at 7:30 a.m. If you have any snowpack or avalanche observations drop us a line at mtavalanche@gmail.com or call us at 587-6984.

STILL TICKETS LEFT:

Montana Ale Works Fundraiser Dinner, this Wednesday

Tickets are on sale now to the 5th Annual Friends of the Avalanche Center Dinner and Wine Pairing on Wednesday, March 13th at 6:00 p.m. Call the host stand at 587-7700 to reserve your space. Tickets are $75 and all proceeds go to the Friends of the Avalanche Center. There are only 40 tickets available and this event sells out every year so get them while you can!

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