GNFAC Avalanche Forecast for Thu Mar 7, 2019

Not the Current Forecast

Good morning. This is Doug Chabot with the Gallatin National Forest Avalanche Forecast issued on Thursday, March 7th at 7:00 a.m. Today's forecast is sponsored by Grizzly Outfitters in partnership with the Friends of the Avalanche Center. This advisory does not apply to operating ski areas.

Mountain Weather

Around Bozeman and Big Sky 1” of snow fell early yesterday morning while the areas around West Yellowstone and Cooke City received 3-5” yesterday and last night. Temperatures at 5 a.m. are in the mid-20s and winds are southwest at 10-15 mph with gusts of 20-30 mph. Today will be mostly cloudy and mountain temperatures may rise to above freezing as winds remain the same. Scattered snowfall this afternoon and tonight will drop 1-2” in the north and 3-4” in the south.

Snowpack and Avalanche Discussion

All Regions

New snow in the last 48 hours (4” in the north and 8” in the south) buried a layer of weak faceted snow that was at the surface. This layer formed over the weekend during cold, clear nights and (relatively) warmer days. Eric and I found it on Buck Ridge (video), the Big Sky Ski Patrol easily triggered slides on it yesterday, and a skier triggered an avalanche on it on Mt. Blackmore (details), but Karl did not find it in Bacon Rind (video). It’s prudent to assume it exists everywhere until you rule it out. Although slides will only involve new snow, they may propagate wide and catch a person off-guard. The two skiers on Blackmore were descending one at a time, a good practice that can save us when things go wrong.

There are two layers of concern in the snowpack, one at the top and another at the bottom. Besides the one at the top, near the ground are facets from December that are deeply buried and difficult to trigger. Ian was in Lionhead on Monday and dug to the ground to look at this deep layer and found improving stability and cautioned us to be patient as it takes days for a snowpack to adjust to such a large load (video). Shallow areas, typically windblown edges of a slope, are potential trigger points for deep slides as are cornice falls.

Winds are gusty enough to blow snow around at the ridgetops. Shooting cracks are signs that wind drifts could slide. A zippy layer of facets under the new snow is something we have not seen this season, so dig hand pits to look for it. For today, avalanches remain possible and the danger is rated MODERATE.

Hot Tip: Use the Regional Pages (top of the webpage) to find out what avalanche activity has been reported in the area you plan to visit.

If you get out and have any avalanche or snowpack observations to share, contact us via our website, email (mtavalanche@gmail.com), 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: Events and Education Calendar.

COOKE CITY

This 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

The accident report for the avalanche fatality in the Bridger Range on February 26th is complete. You can view the report here.  


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