Good Morning. This is Mark Staples with the Gallatin National Forest Avalanche Advisory issued on Friday, January 15, at 7:30 a.m. The Hans Saari Memorial Fund, in cooperation with the Friends of the Avalanche Center, sponsor today's advisory. This advisory does not apply to operating ski areas.
After 7 a.m. yesterday another inch of snow fell in most areas bringing the storm total to nearly 3 inches. Overnight partially clear skies allowed temperatures to drop into the high teens and low 20's F. Today will be partly sunny with temperatures reaching the low 30's F. Strong winds will be the most exciting part of the forecast. This morning they were blowing in the 30's mph from the W at the Bridger Ridge while blowing 15-35 mph SSW near Big Sky and much calmer near West Yellowstone and Cooke City. Expect winds to increase early this afternoon when they will blow 20-30 mph from the WSW with gust in the 40's especially in the Bridger Range.
With several inches of new snow and strong winds, newly formed wind slabs can be found near ridgetops and other terrain features where wind-blown snow collects. Ski patrollers at Big Sky found wind slabs 4-6 inches thick while a few were up to a foot thick and were easily triggered with ski cuts. Eric and I skied Saddle Peak yesterday where we carefully avoided any wind-blown snow knowing that even a small avalanche could cause serious injuries if it swept us in to trees or over rocks. Fortunately fresh wind slabs are relatively easy to identify and avoid.
Unfortunately another avalanche concern lies much deeper in the snowpack and is harder to avoid because it exist throughout the advisory area. Weak faceted snow buried about 3 ft deep produced the most widespread avalanche cycle in the past 20 years immediately following last week's storm. During that avalanche cycle this layer was extremely sensitive on all slopes. Since then variability of this layer has increased as it is weaker on some slopes than on others. The only way to assess this layer is to dig a snowpit and conduct stability tests. Even on small sheltered slopes well below tree line this layer remains a concern and we continue to receive reports of poor stability test results and collapsing and cracking on such slopes. Some of these sheltered slopes near Big Sky, West Yellowstone, and Cooke City contain a layer of surface hoar buried by recent snowfall. This layer will be a greater stability concern when more snow falls.
With time all things heal, unfortunately buried facets require extra time. In the pursuit powder and the perfect turn, we as humans often do not give such things enough time and I worry. Today human triggered avalanches are probable on any slope with wind drifted snow or any slope steeper than 35 degrees where the avalanche danger is rated CONSIDERABLE. Less steep slopes without wind drifted snow have a MODERATE avalanche danger.
I will issue the next advisory tomorrow morning at 7:30 a.m. If you get out in the backcountry give us a call or email with your observations. You can reach us at 587-6984 or email us at mtavalanche@gmail.com.
Avalanche Education
1. University of Montana/ Western, Room 311 Block Hall, Dillon, MT
One-hour Avalanche Awareness Class - Friday, January 15th - 7pm to 8pm
2. Cooke City Fire Hall
One-hour Avalanche Awareness Class - Saturday, January 16th - 6pm to 7pm
3. Bozeman
MMA Teen Avalanche Class: Lecture Thursday, January 21st & Field Session Saturday, January 23rd. To sign up or get more information, call Erin Taylor Montana Mountaineering Associations at 522-0659
4. Bridger Bowl
AAI Level 1 Avalanche Course - Friday, January 22nd to Sunday, January 24th
www.americanavalancheinstitute.com
5. Four Corners Groomer Shack
RESCUE LECTURE: Tuesday, January 26th 7pm. The Gallatin Valley Snowmobile Association is having it annual Chili Feed at 6:30pm in the Groomer Shack at 4 corners.
6. Billings
Avalanche Awareness and Rescue Class-Wednesday, January 27th, 6-9 pm at Beartooth Harley.
7. Bozeman
BASIC AVALANCHE WORKSHOP: The Friends of the Avalanche Center and ASMSU Outdoor Rec are offering a Basic Avalanche Awareness Class the evenings Wed, Thur, 27 & 28 January with a field day on Saturday, 30 January. $25 donation. No sign up required. http://www.mtavalanche.com/education/classes/basic
8. Holiday Inn, West Yellowstone
One-hour Avalanche Awareness Class - Saturday, January 30th - 7pm to 8pm