Good morning. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Saturday, December 24 at 7:30 a.m. This advisory is sponsored by Montana Import Group in partnership with the Friends of the Avalanche Center. This advisory does not apply to operating ski areas.
A dry and mild weather pattern will persist over southwest Montana through the holiday weekend. Santa will likely have smooth sailing while making his rounds tonight into tomorrow. Currently – mountain temperatures are in the mid teens to low 20s and winds are blowing predominately out of the west at 15-30 mph. Today, temperatures will rise into the mid to high 20s under partly cloudy skies and winds continue to blow 15-30 mph out of the WNW.
The Bridger Range, Gallatin and Madison Ranges, the Lionhead area near West Yellowstone and mountains around Cooke City:
T'was the day before Christmas
and all through the hills
not a snowflake was falling
but the winds delivered chills
The new snow was blown
into puffy wind rolls
which can easily fail
if you pick the wrong knoll
When out in the backcountry
Dig a pit before you slide
Look for the weak layers
That could take you for a ride.
Yesterday, two skiers in Beehive Basin escaped with their hide, after skiing a steep slope and triggering a slide (photo1, photo2). The avalanche occurred on a west facing slope around 9,000 ft and failed on well developed facets near the ground. The Moonlight Basin Ski Patrol also triggered numerous slides during control work on Thursday. Both are prime indicators that the weak snow structure of the northern Madison Range is having difficulty supporting the most recent load (snowpit).
These two examples illustrate what's possible throughout our advisory area. Although southwest Montana has not received any new snow since Wednesday, strong winds have been loading leeward slopes (photo). Winds have been blowing predominately out of the west, making slopes on the east half of the compass most prone to slab development. However, the east wind event this past Wednesday/Thursday did deposit additional snow on west facing slopes.
Today, the primary avalanche concern will be slopes that have received wind deposited snow. Recently formed wind slabs will likely be resting over a weak foundation of buried facets (video), making them sensitive to the weight of skier or rider.
Today natural avalanches are possible and human triggered avalanches are likely on all wind loaded slopes where the avalanche danger is rated CONSIDERABLE. Slopes that have not received a wind load have a MODERATE avalanche danger.
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
BOZEMAN
Women’s 1-hour Avalanche Awareness Lecture. Wednesday, January 4, 6:30- 8 p.m. at REI.
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.
1-hr Avalanche Awareness Lecture. Wednesday, January 11, 6:30-7:30 p.m at REI.
BIG TIMBER
1-hr Avalanche Awareness Lecture. Tuesday, January 10, 7-8 p.m at Big Timber High School.
HELENA
1-hr Avalanche Awareness Lecture. Thursday, January 12, 6:30-8:30 p.m at Exploration Works.
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.