Good morning. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Monday, December 8 at 7:30 a.m. Today’s 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 stationary ridge of high pressure has produced quiet weather over southwest Montana. This morning, mountain temperatures are in the upper 20s to low 30s F under mostly clear skies and winds are blowing 10-20 mph out of the WSW. Today, temps will warm into the mid to upper 30s F and winds will remain light to moderate out WSW. High pressure will continue to dominate the weather pattern over the next few days.
Cooke City
The snowpack around Cooke City is showing signs of improvement. Warmer temperatures and consistent snowfall are helping facets near the ground gradually become stronger. Yesterday, Doug and his partner rode extensively north of town. They observed only one recent avalanche and had mixed results in stability tests. The avalanche was a natural that occurred on the southeast side of Crown Butte, likely the result of a heavy wind load (photo). Stability tests revealed facets on north facing slopes near the ground were the weakest, but even those were taking hard force to impact (video).
As usual in Cooke City, there are very few upper elevation slopes not affected by the wind. As Doug's photo indicates, strong winds over the past few days have stripped many slopes and loaded others. The slopes that have been heavily wind loaded are the most likely to produce an avalanche. Today, the best bet is to avoid riding in steep alpine terrain all together.
While stability continues to improve, human triggered avalanches are likely on wind loaded slopes steeper than 35 degrees which have a CONSIDERABLE avalanche danger. All other slopes have a MODERATE avalanche danger.
Bridger Range Gallatin Range Madison Range Lionhead area near West Yellowstone
Overall - stability in the mountains around Bozeman, Big Sky and West Yellowstone continues to improve. However, sugary facets near the ground are still a concern. And the pattern of strong and weak snow is not uniform – a snowpit on one slope may not be representative of the snowpack on another slope.
Yesterday, I joined nearly one hundred participants in the ASMSU field session north of Bridger Bowl. Snowpack variability was apparent in the dozens of snowpits and stability tests we conducted on various aspects. Most stability tests pointed towards a strengthening snowpack, but a handful yielded unstable results (video). The weakest snow we found was on north facing slopes above 8,000 ft. These findings are consistent with what we’ve been seeing throughout much of our advisory area.
Today, evaluate the snow and your terrain choices carefully. Avoid dropping into upper elevation slopes, especially those in steep, rocky terrain facing the north half of the compass. Today – human triggered avalanches are possible and the avalanche danger is rated MODERATE.
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.
Have a Smartphone or Tablet? The Friends of the Avalanche Center just published two FREE apps so you can get the latest avalanche information, videos and photos: iOS 8 GNFAC App; Android app
AVALANCHE EDUATION and EVENTS
Take a look at our Education Calendar for all our classes being offered.
Avalanche Awareness (1-hour), Wednesday, December 10, 6:30 p.m. at REI, Bozeman
Avalanche Awareness (1-hour), Thursday, December 11, 6 p.m. at Summit Motorsports, Bozeman
Weather Workshop, Thursday, December 11, 6:30 p.m. at REI, Bozeman
Fundraiser at Katabatic Brewing, Tuesday, December 16, 4-8 p.m., Livingston
Avalanche Awareness and Beacon Practice, Wednesday, December 17, 6:30-8:30 p.m. at Beall Park, Bozeman
Snowmobiler Introduction to Avalanches with Field Course
West Yellowstone: Dec 18 and 19, 2014: https://www.ticketriver.com/event/12955
Five hours of lectures are followed by a full day field course. Topics covered include: avalanche terrain recognition, the affect weather has on avalanche hazard, the development of the mountain snowpack, decision making skills, and basic search and rescue procedures.