Good morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Tuesday, January 18, at 7:30 a.m. Alpine Orthopedics, in cooperation with the Friends of the Avalanche Center, sponsors today’s advisory. This advisory does not apply to operating ski areas.
The mountains picked up more snow yesterday. Cooke City got the most with 6-8 inches while West Yellowstone got the least with 2 inches; 3-4 inches fell everywhere else. Ridgetop winds averaged 25-30 mph with gusts exceeding 40 mph. Temperatures have cooled into the teens from the low 30s yesterday morning. Clouds will increase today as winds remain steady at 20-30 mph out of the west to north. Another moist system will bring snowfall tonight blanketing us with 3-6 inches of new snow by morning.
The mountains around Cooke City and the Washburn Range:
The mountains around Cooke City have been the clear winner with almost three feet (2.4” SWE) of new snow in the last 72 hours. Wind drifts made backcountry travel difficult yesterday. The GNF Snow Rangers couldn’t even break trail on their sleds to Daisy Pass because of the deep snow. On Sunday, skiers triggered a wind slab near Lulu Pass. With even more snow and strong west to northwest winds, I’m betting that there are many natural avalanches on wind-loaded slopes today which have a HIGH avalanche danger. All other slopes have a CONSIDERABLE danger.
The Bridger, Madison and Gallatin Ranges including the Lionhead area near West Yellowstone:
Since Saturday evening about 6-8 inches has fallen in the northern mountains with 12-14 inches accumulating down south. Over the last six weeks we’ve been very concerned with a buried surface hoar layer near Big Sky, but we’ve been tracking it closely and watched it gain strength. I dug four pits on Sunday looking for it, and although I could still barely see it in the pit wall, it would not fracture in any of my stability tests. If it does exist, it’ll be on small, isolated slopes. The snowpack is no longer like punished child standing alone in a corner separated from everyone else; it’s finally behaving.
There are two stability issues to watch out for. The first, and most obvious, is wind-loaded slopes which could be easily triggered. The second, more subtle issue is slopes with a thin snowpack. We are finding that snows less than three feet deep have gotten weaker and more unstable as facets near the ground have lost strength and cohesion. We have found this in Beehive Basin (video) and in the Bridger Range on a few west facing slopes as well as Argentina Bowl near Saddle Peak (video). Skiers reported finding this up Hyalite and also in the southern Madison Range. A thin snowpack is often comprised of sugary, weak facets and will not support new snow very well.
For today, the avalanche danger on all wind-loaded terrain is CONSIDERABLE. All other slopes have a MODERATE 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.
SURVEY
The Friends of the Gallatin National Forest Avalanche Center are sponsoring a survey. We’re trying to find out how we're doing, what we can do better and who our users are. The survey is 4 pages long and takes 5-10 minutes to complete. http://www.surveymonkey.com/s/YFCKDZH
Beacon Park Opening Celebration
The Bozeman Recreation Department is celebrating the opening of the Bozeman Beacon Park on Friday, January 28th from 4:00 to 6:00 p.m. at Beall Park, 415 N. Bozeman. The Recreation Department will offer food, refreshments, music, and training on how to use the park with your avalanche beacon. This event is free to the public. For information call 582-2290.
Avalanche Education
January 18, TONIGHT in Cody, WY
The Friends of the Avalanche Center will be sponsoring a FREE 1 hr Basic Avalanche Awareness at Mountain Valley Motorsports – 7 p.m. to 8 p.m. Call 307-587-6218 for more info.
January 19, TOMORROW in Bozeman
The Friends of the Avalanche Center will be sponsoring a FREE 1 hr Basic Avalanche Awareness at REI – 6:30 p.m. to 7:30 p.m. Register at www.rei.com/bozeman
January 26, 27 and 29 in Bozeman
Basic Avalanche Awareness – Next Wednesday & Thursday 7:00 p.m. – 9:30 p.m. at MSU EPS Building, Room 103 with a field day on Saturday at Bridger Bowl (more information) (Prepay)
February 2, 3, and 5 in Bozeman
Advanced Avalanche Awareness –Wednesday & Thursday 7:00p.m. – 9:30 p.m. at MSU SUB Room 235 with a field day on Saturday at Bridger Bowl (more information) (Prepay)
For additional information and a listing of other avalanche classes, go to: http://www.mtavalanche.com/workshops/calendar