Good morning. This is Mark Staples with an early season avalanche information bulletin issued on Friday, November 25 at 7:30 a.m. This bulletin is sponsored by Gallatin County Search and Rescue. Please remember that uphill traffic is not allowed at Big Sky or Moonlight Basin Ski areas. Uphill traffic is permitted at Bridger Bowl, but backcountry snow conditions exist.
At 4 a.m. ridgetop winds were blowing 20-30 mph mostly from the S and temperatures were in the 20s F. This morning as a cold front approaches, winds will increase and blow 20-40 mph from the W. Temperatures should drop throughout the day into the teens F and colder by tonight. Snowfall will begin sometime this morning and end this evening. The mountains near West Yellowstone and Cooke City should get 2-4 inches and the mountains near Bozeman and Big Sky should get 1-3 inches. Warmer and drier weather will move back over the area for the weekend.
It’s black Friday, one of the biggest shopping days of the year. If you are shopping for weak faceted snow, then you’re in luck. This layer can be found near the ground in many areas. When you find this layer, you get the added bonus of either very low stability test scores or natural and human triggered avalanches.
Much of this avalanche activity has occurred in Hyalite Canyon (photo, video) and on Lone Mountain where the Big Sky Ski Patrol has easily triggered many avalanches on this layer. Skiers have also found this layer in Beehive Basin, the northern Bridger Range, and Targhee Pass near West Yellowstone. In some cases these facets rest on an ice crust, in other areas they do not. Either way, this layer has demonstrated the ability to produce avalanches.
Strong winds this week, loaded many slopes and gullies. These locations likely have a stiff wind slab resting on facets near the ground, a good recipe for an avalanche and I would avoid these locations. Today’s snowfall and strong winds will only add more stress to these slopes and make avalanches more likely.
Yesterday in the Bacon Rind area of the southern Madison Range, Eric found a surprisingly supportable snowpack even though it was only 20 inches deep. He found facets near the ground, but they did not seem as weak as in other areas. In the mountains near Cooke City, we have limited data, but we know this area has received a steady supply of snow and wind with more coming. This combination alone can easily produce avalanches.
We are not issuing avalanche danger ratings due to limited snowpack data. We need your backcountry observations to help us. Any snowpack or avalanche information is especially valuable this time of year. If you get out, please drop us a line at mtavalanche@gmail.com or leave us a message at 587-6984.
Wednesday, November 30, BOZEMAN
Introduction to Avalanches with Field Course at MSU. Wednesday and Thursday evening lectures with a field course on Saturday. More info at http://www.mtavalanche.com/education/classes/workshops
Tuesday, December 6th Beartooth Harley, Billings – Basic 1 hr Avalanche Awareness
More info at http://www.mtavalanche.com/workshops/calendar
Tuesday, December 6th 406 Brewery, Bozeman – Basic 1hr Avalanche Awareness
More into at http://www.mtavalanche.com/workshops/calendar
Wednesday, December 7th, REI Bozeman – Basic 1 hr Avalanche Awareness
More into at http://www.mtavalanche.com/workshops/calendar
Wednesday, December 7th Livingston - Snowmobiler Introduction to Avalanches with Field Course, Wednesday and Thursday evening lectures with a field course on Saturday. More info at http://www.mtavalanche.com/education/classes/workshops
Thursday, December 15th West Yellowstone – Snowmobile Guides Course. Lectures on Thursday - field day on Friday. More info at http://www.mtavalanche.com/workshops/calendar