Good morning. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Monday, December 12 at 7:30 a.m. This advisory is sponsored by Grizzly Outfitters and Madison River Brewing Company does not apply to operating ski areas.
A split jet stream is diverting active weather patterns to the north and south, leaving southwest Montana in a doughnut hole. Currently mountain temperatures are in the mid teens F and winds are blowing 5-15 mph out of the SSE under partly cloudy skies. Today, temperatures will warm into the mid 20s F and winds will shift to the SSW blowing 10-20 mph.
The Bridger, Gallatin and Madison Ranges, the Lionhead area near West Yellowstone and mountains around Cooke City:
Looking at the 6-10 day forecast, it does not appear that any number of pray for snow parties or burned pair skis will pull us out of this dry pattern. If it’s not going to snow at least we can take a small amount of comfort in the fact it’s not 20 below zero.
In most areas snowpack depths and structure have changed little over the past week. It’s still possible to find weak sugary facets near the ground, capped by various crusts or denser layers of facets (photo). Although this structure is set up to be potentially unstable, we have received very few reports of avalanche activity or signs of instability. Without any sort of new load, the snowpack seems to be in a holding pattern.
While the snowpack appears to be less reactive this week than last, we still have persistent weak layers buried throughout the pack (snowpit). This warrants caution when traveling in the backcountry.
If a slope has more than two feet of snow or a wind load, the possibility of a slab resting over facets does exit. This type of structure makes human triggered avalanches possible and the avalanche danger is rated MODERATE.
On slopes where the snowpack is less than two feet deep, there likely isn’t enough slab/load to facilitate crack initiation and fracture propagation. For this reason, slopes with less snow have a LOW avalanche danger.
Doug 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.
EVENTS/EDUCATION
To check out all our education programs: http://www.mtavalanche.com/workshops/calendar
WEST YELLOWSTONE
Snowmobiler Introduction to Avalanches with Field Course. Lectures on Thursday, December 15 with an all day field course on Friday, December 16. Advanced registration is NOT required, but encouraged.
BOZEMAN
Snowmobiler Introduction to Avalanches with Field Course. Lectures on Saturday, January 7, with an all day field session Sunday, January 8. Advanced registration IS REQUIRED.
CODY, WYOMING
Snowmobiler Introduction to Avalanches with Field Course. Lectures on Saturday, January 14 at Mountain Valley Motorsports with an all day field session near Cooke City on Sunday, January 15. Advanced registration IS REQUIRED.