Good Morning. This is Eric Knoff with early season snowpack information issued at 7:30 a.m. on Wednesday, November 11. Today’s information is sponsored by Grizzly Outfitters in partnership with the Friends of the Avalanche Center. This information will be updated as weather and snow conditions change.
Yesterday’s storm favored the Bridger Range, which picked up 5” of new snow. The mountains around Big Sky, West Yellowstone and Cooke City received 2-3” of new snow. This morning, temperatures range from the single digits to low teens F and winds are increasing out of the west-southwest, with the exception of Cooke City where winds are blowing out of the northwest. The ridge weather station at Bridger Bowl is showing wind gusts in excess of 40 mph, while winds around Hyalite and Big Sky are gusting close to 30 mph. Today, temperatures will warm into the 20s F and winds will continue to be moderate to strong out of west. Skies will be partly cloudy this morning, but will become increasingly cloudy by this afternoon. A weak weather system will push into the area later today producing a slight chance of mountain snow showers this evening. The mountains could pick up a trace to one inch of new snow by tomorrow morning. Warmer and drier conditions look to be on hand for the weekend.
Yesterday’s storm delivered 2-5” of new snow to our forecast area, adding to a preexisting base of 12-20”. This puts the settled base depth at 1.5 to 2 feet in most areas above 8,000 feet. In the mountains around Cooke City, skiers reported finding close to three feet of settled snow in upper elevation terrain.
While 2-5” of new snow isn’t enough to spike the avalanche danger, there are a few avalanche problems to consider. The primary concern today will be wind loaded slopes. Strong winds this morning out of the west-southwest will make east and north facing slopes the most likely to harbor fresh wind slabs. This problem will be most prevalent below upper elevation ridgelines and on the leeward side of cross loaded gullies.
Wind-loaded slopes should be approached carefully and avoided completely if they show signs of instability such as cracking or collapsing on approach - or if recent avalanche activity is present. As two hunters found out last Thursday, it doesn’t take much snow and wind to create unstable conditions (photo). On Sunday, a skier north of Emigrant Peak in the Absaroka Range also triggered a sizeable wind slab, narrowly escaping a nasty ride (photo, photo).
Aside from wind loaded slopes there shouldn’t be much in the way of avalanche hazard. Average to above average temperatures before this storm allowed the existing snowpack to gain strength, proving a strong foundation for the new snow. Because this storm came in warm and left cold, the new snow should be well bonded to the old snow surface. There may be some loose snow activity in steep terrain, but I don’t expect slab avalanches to occur on slopes that haven’t been wind loaded.
While avalanches remain a concern, there are plenty of other hazards to be aware of in the backcountry. Shallow, early season conditions exist, making stumps, rocks and other immovable objects a constant threat. Be aware of the changing snow and weather conditions that El Nino brings (video) and always be prepared for the unpredictable and unforgiving conditions that come with early season riding.
We are not issuing danger ratings until we begin daily avalanche forecasts, which is dependent on snowfall. In the meantime, we will update this information as conditions change. We need your observations, so please drop us a line if you get out: mtavalanche@gmail.com.
AVALANCHE EDUCATION
A complete calendar of classes can be found HERE.
November 11, 8:30 a.m. to 7:30 p.m., Bozeman, Montana State University, MSU Snow and Avalanche Workshop: http://www.montana.edu/snowscience/workshop/index.html
November 17, 6 p.m.: Billings, Avalanche Awareness at Basecamp.
November 18, 6 p.m.: Bozeman, Avalanche Awareness at MSU Roskie Hall
November 18, 7 p.m.: Big Sky, Avalanche Awareness at Grizzly Outfitters.
November 19, 7 p.m.: Big Timber, Avalanche Awareness at Sweet Grass County High School
Gallatin County Search and Rescue's Winter Backcountry Hasty team is having an orientation for new and established members on November 23rd (1830hrs) at the SAR building at the SE corner of the fairgrounds. This group responds to winter backcountry SAR events and requires excellent winter backcountry and avalanche skills. If you would like to join, please contact Scott at helialpha@gmail.com.
MSU - Introduction to Avalanches with Field Course
Workshops are held on Wednesday and Thursday evenings, with a field course on Saturday. Different topics are presented each evening. Topics include: avalanche terrain recognition, the affect weather has on avalanche hazard, the development of the mountain snowpack, decision making skills, and basic search and rescue procedures.
December 2, 3 and 5 or 6, 2015: https://www.ticketriver.com/event/16858
West Yellowstone: Snowmobiler Introduction to Avalanches with Field Course
Five hours of lectures are followed by a full day field course. Topics include: avalanche terrain recognition, the affect weather has on avalanche hazard, the development of the mountain snowpack, decision making skills, and basic search and rescue procedures.
December 17 and 18, 2015: https://www.ticketriver.com/event/17356