This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Monday, January 2 at 7:30 a.m. This advisory is sponsored by Gallatin County Search and Rescue in partnership with the Friends of the Avalanche Center. This advisory does not apply to operating ski areas.
AVALANCHE FATALITIES
There were two avalanche fatalities outside Cooke City on Saturday. A snowmobiler triggered and was buried in a slide on Mt Henderson above Fisher Creek. The crown was 1-4 feet deep, 300-400 feet wide and ran a total of 1,200 vertical feet (photo, video). The rider was buried 2-3 feet deep and was recovered within 10-15 minutes. A skier south of Cooke City in Hayden Creek was also buried and killed in an avalanche. He triggered the slide near the bottom of the slope, but it broke well above him burying him at least 3 feet deep. Doug is investigating this avalanche today and we will have completed reports later in the week. Our condolences go out to both families.
A building ridge of high pressure will bring sunny and unseasonably warm conditions to southwest Montana today. Currently mountain temperatures are in the mid twenties to low thirties with the exception of the mountains around West Yellowstone and Cooke City where temperatures are in the mid teens. Winds are blowing 10-20 mph out of the WSW and will gradually increase to 15-30 mph by this afternoon. Clear skies and warmer temperatures are expected through tomorrow.
The Bridger, Madison and Gallatin Ranges, the Lionhead area near West Yellowstone and the mountains around Cooke City:
On Saturday, avalanches claimed the lives of two individuals. This equals the total number of fatalities that the entire state of Montana experienced all of last season. Aside from the two separate avalanches that resulted in fatalities, numerous natural and human triggered avalanches were reported throughout southwest Montana over the holiday weekend.
This spike in avalanche activity is the direct result of a rapid and heavy load (1.5-4" of SWE) being deposited on top of a very weak snowpack. The layer of concern is the interface between the recent storm snow and the older, weaker facets near the ground. Any slope that has received additional loading due to wind is especially susceptible to avalanches.
I spent the past three days in Cooke City and was amazed by the sheer volume of avalanche activity. Natural and human triggered avalanches were widespread and many slides were triggered from either the bottom of the slope or from adjacent slopes, a clear sign of highly unstable conditions (video). Doug and Mark found similar conditions near Hebgen Lake on Saturday (photo). In addition, all the local ski patrols have experienced extensive avalanche activity during control work, most notably on wind-loaded slopes.
For today – the avalanche danger is rated HIGH on all wind loaded slopes where human triggered avalanches remain very likely. A CONSIDERABLE avalanche danger exists on non-wind loaded slopes. All avalanche terrain, including avalanche run-out zones, should be avoided.
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
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.
BILLINGS
Snowmobiler Introduction to Avalanches with Field Course. Lectures on Tuesday, January 24 from 6-9 p.m. at Hi-Tech Motor Sports with an all day field session in Cooke City on Sunday, Jan 29. PRE-REGISTER BY JAN 23 at Hi-Tech!! Register with Sharon at 406-652-0090; hitech@hi-techmotorsports.com.