GNFAC Avalanche Advisory for Tue Mar 2, 2010

The Bridger, Madison and Gallatin Ranges, the Lionhead area near West Yellowstone, the mountains around Cooke City and the Washburn Range:

If you were thinking that all the recent sunshine and warm temperatures made the avalanche danger go away, well, think again. Yesterday, skiers sent in photos of a deep slab avalanche from the Hyalite area (photo1, photo2, photo3) that ran 1,200 feet.  They kicked off a large cornice which triggered the slide on facets at the ground. These facets were formed back in early December, back when the snowpack was young and winter was full of hope.  Here we are three months later still seeing avalanches on this layer.  On Sunday, another group of skiers in the northern Gallatin Range found weak snow 10 inches under the surface.  These small grained facets were breaking clean and easy in their stability tests (photo). This layer is found one to two feet deep throughout southwest Montana with feathery crystals of surface hoar thrown into the mix.  For now, these two distinct layers, one near the surface and the other near the ground, are the main stability concerns. 

A few wet, loose natural avalanches occurred on the south face of Beehive Ridge yesterday.  The upper elevations warmed to near 40 degrees with the sun climbing higher and solar radiation getting stronger by the day.  All the ski patrols, as well as a backcountry skier near Ross Pass in the Bridger Range, found the surface snow saturated and avalanching in point release slides on south to east facing slopes.  With today being another warm day, wet slides will become more numerous.

Even though folks are walking around town in sandals and t-shirts, the snowpack is still stuck in winter. Other than the top few inches of snow getting warm, the rest of the pack is below freezing which keeps the facets preserved.  Yesterday's avalanche up Hyalite could have happened anywhere in our forecast area; the same ingredients are found in all the ranges.  For today, given the persistent weak layers and recent avalanche activity, the avalanche danger continues to be rated MODERATE.

I will issue the next advisory tomorrow morning at 7:30 a.m. If you get out in the backcountry let us know what you find.  You can reach us at 587-6984 or email us at mtavalanche@gmail.com.

Avalanche Education & Events

1.Bozeman

Join us to discuss the snowpack, weather, and circumstances leading up to the avalanche on Saddle Peak.  We will show videos, pictures, and share stories about this popular sidecountry destination. Cost: Free, When: Thursday, March 4 from 6:30-7:30 p.m., Where: Bozeman Public Library meeting room.

2. Bridger Bowl

29^th Annual Pinhead Classic on Saturday, March, 6^th.  "Carnival" is this year's costume theme, so come dressed up to race, socialize and win great prizes. Registration fee is $30 but gets you all sorts of cool stuff. Check out the website http://pinheadclassic.com for details.

3. Moonlight Basin

Comprehensive avalanche awareness class - Thursday, March 4^th to Saturday, March 6^th

events@moonlight.com or 406-993-6026

4. Bell Lake Yurt, Tobacco Root Mountains

Montana Backcountry Adventures - Comprehensive avalanche awareness class

Wednesday, March 12^th to Friday, March 14^th

For more info call 995-3880 or go to www.skimba.com