Good morning. This is Mark Staples with the Gallatin National Forest Avalanche Advisory issued on Friday, January 9, at 7:30 a.m. Today’s advisory is sponsored by a Montana FWP Recreation Trails Grant. This advisory does not apply to operating ski areas.
This morning no new snow was recorded at remote weather stations, but some places like Bozeman received a dusting of snow. Temperatures were in the low teens F in the mountains and single digits in valley locations. Light, westerly winds were only blowing 5-10 mph at ridgetops. Today will be a great one to be in the mountains with sunshine, light winds, and temperatures warming into the upper 20s F.
Bridger Range Gallatin Range Madison Range
Lionhead area near West Yellowstone Cooke City
Triggering an avalanche remains definitely possible. Avalanches should be confined to smaller pockets breaking 1-3 feet deep. A group riding near Cooke City on steep, treed slopes triggered a slide on Wednesday near Lulu Pass. They also triggered one yesterday near Daisy Pass about 100 feet wide, 150 feet long, and several feet deep. Two were caught but not buried yesterday. These slides are good reminders to expose one person at a time and to make sure to keep eyes on our partners even when crossing small slopes. Simple tasks but hard to do when riding in thick trees.
Assessing stability today is easy. Look for and test weak layers buried 1-3 feet deep. Repeat this process if you move to a different area, because the distribution and stability of these weak layers does not have a clear pattern.
- Pick a small, low angle slope (less than 30 degrees) in the area where you hope to ski or ride. (see where to dig in this video)
- Dig 3 feet deep in a spot without old ski or snowmobile tracks and not right next to a tree.
- Perform a quick Extended Column Test (see how in this video)
- If you see a stripe in the snow (the weak layer) and it propagates a crack across the full column, that’s bad. If it doesn’t propagate, that’s good. If you can’t find any weak layer, that’s good too.
There have been avalanches like the ones near Cooke City mentioned above, one seen near Cooke City on Monday (photo) and a few I saw near Big Sky from early this week (photo1, photo2). The heavy load of snow from Sunday and Monday added a lot of stress to the snowpack. We thought more avalanches would have occurred, but there have been surprisingly few, a good sign. Eric and his partner tested two buried surface hoar layers in the snowpack yesterday in the southern Madison Range. One surface hoar layer (9 inches deep) was unreactive, while the second (21 inches deep) propagated and produced one big collapse, a sure sign of instability.
With pockets of instability lurking on isolated slopes, heightened avalanche conditions exist in specific places but these slopes are hard to identify without putting your shovel in the snow and testing buried weak layers. Today the avalanche danger is rated MODERATE.
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.
AVALANCHE EDUATION and EVENTS
Take a look at our Education Calendar for all our classes being offered.
Companion Rescue Clinic, Bozeman, Friday eve and Saturday field, January 9 and 10, REI. Register for the class here: www.rei.com/stores/bozeman.html
1-hour Avalanche Awareness for Snowmobilers, West Yellowstone, 7 p.m., Saturday, January 10, Holiday Inn.
1-hour Avalanche Awareness, Three Forks, 7 p.m., Monday, January 12, Methodist Church Annex.
Women’s Avalanche Awareness w/ Beacon Practice, Bozeman, 6:30- 8 p.m., Tuesday, January 13, Beal Park.
1-hour Avalanche Awareness, 4 Corners, 6:30 p.m., Wednesday, January 14, GVSA Groomer Shed.
1- hour Sidecountry Avalanche Awareness, Bozeman, 6:30-8 p.m., Wednesday, January 14, REI.
Companion Rescue Clinic, Cooke City, 9 a.m.-3 p.m. on Sunday, January 18. More details and registration: https://www.ticketriver.com/event/13990
Introduction to Avalanches with Field Course, MSU Bozeman, evening lectures 7-9:30 p.m. Wednesday and Thursday, January 21 and 22, with an all-day field session on Saturday or Sunday (your choice). Get more information and register here: https://www.ticketriver.com/event/13090
Advanced Avalanche Workshop with Field Course, MSU Bozeman, evening lectures 7-9:30 p.m. Wednesday and Thursday, January 28 and 29, with an all-day field session on Saturday. Get more information and register here: https://www.ticketriver.com/event/12445
The Friends of the Avalanche Center and Montana Ale Works are hosting an Avalanche Forecaster’s Beer Social Fundraiser the evening of January 27th. Get more information and buy tickets here: https://www.ticketriver.com/event/14010