Good morning. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Sunday, December 11 at 7:30 a.m. This advisory is sponsored by Cooke City Motorsports and Yamaha and does not apply to operating ski areas.
High pressure remains the dominant weather pattern over southwest Montana. This morning skies are clear and mountain temperatures are between 15-20⁰ F. Winds are blowing out of the WSW at 5-20 mph. Today, skies will start out clear but become partly cloudy by this afternoon. Temperatures will rise into the mid 20s to low 30s and winds remain light out of the WSW.
The Bridger, Gallatin and Madison Ranges, the Lionhead area near West Yellowstone and mountains around Cooke City:
It's been over a week since any measurable amount of snow has fallen over southwest Montana. Since then the snowpack has felt the effects of warm days and cold nights, especially in areas with less than two feet of snow.
Yesterday, my partner and I toured up Mt Ellis. We found a variety of facets in the snowpack and growing surface hoar on shady aspects (snowpit, photo). We did not experience any cracking or collapsing and did not get unstable results during our stability tests. On the way down my partner made the comment "facets make great skiing", which they do, as long as they don't have a large load on top of them. A skier found similar conditions at History Rock (photo).
Yesterday, Doug was ice climbing and hiking in steep gullies in Hyalite Canyon. He also did not experience any cracking or collapsing, but felt triggering a slide was still possible in steep wind loaded terrain. This is consistent with reports from the Moonlight Basin, Big Sky and Bridger Bowl Ski Patrols.
Due to the absence of any significant load it is becoming harder to trigger avalanches. Nevertheless, it is still possible to find slopes with unstable snow. Upper elevation slopes, especially slopes with a wind deposited snow, will be the most prone to avalanches.
If you are heading into the backcountry, keep your avalanche radar on. Now is not the time to let your guard down. If you are caught in an avalanche consequences will likely be severe.
Today human triggered avalanches are possible and the avalanche danger is rate MODERATE.
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.
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.