Good morning. This is Mark Staples with the Gallatin National Forest Avalanche Advisory issued Friday, December 6 at 7:30 a.m. The Yellowstone Club Community Foundation in partnership with the Friends of the Avalanche Center sponsors today’s advisory. This advisory does not apply to operating ski areas.
It’s cold. This morning temperatures were near -20 degrees F, and winds were barely blowing. Unfortunately today will have some clouds and high temperatures will struggle to reach the negative single digits. Winds will increase from the SW and blow 10-15 mph which will feel like a lot with such cold temperatures. There’s a chance for snow today but no accumulation.
Cooke City
Yesterday Doug investigated recent avalanches near Cooke City (photo1, photo2, photo3). Most were breaking 3-4 feet deep on northerly aspects following a large storm at the beginning of the week. Today more human triggered avalanches are likely especially on northerly facing slopes. These slides will break on weak faceted layers of snow found 1-2 feet above the ground. Avalanches today and this weekend will be tricky because they may slide when the first person rides on a slope or they might wait for the second, third, or even tenth person. The point is don’t be fooled by tracks on a slope. Seeing tracks just means someone got lucky. Today the avalanche danger is rated CONSIDERABLE.
Madison Range Gallatin Range
Lionhead area near West Yellowstone
The storm at the beginning of the week brought less snow to other areas. Less storm snow storm generally means fewer avalanches. We have limited data in the Gallatin and Madison Ranges and mountains near West Yellowstone, but some of the weakest snow appears to be near Big Sky. The Big Sky Ski Patrol has triggered many avalanches on facets near the ground in north facing terrain on Lone Mountain.
The snowpack nearby in Beehive Basin also has facets near the ground that can fracture and produce an avalanche (snowpit). I suspect a similar snowpack exists along Buck Ridge. An experienced backcountry skier put it best “I don’t trust the snowpack right now, it has horrible structure.” Overall today the avalanche danger is rated MODERATE and triggering an avalanche is definitely possible. Personally, I wouldn’t trust the snowpack much either and would be very careful in my snowpack evaluations and terrain choices.
Bridger Range
Yesterday the Bridger Bowl Ski Patrol observed some wind blowing downhill that formed sensitive slabs. These slabs avalanched 8-10 inches deep with ski cuts. The good news is that the ski patrol did not trigger any avalanches breaking deeper in the snowpack. The Bridger Range generally has a strong snowpack and most avalanches should be confined to the new snow as Doug and I found on Tuesday (video). Look for isolated areas with evidence of any wind that may have formed a slightly stiffer slab on top of the new snow. Today in the Bridger Range the avalanche danger is 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.
EVENTS/EDUCATION
BOZEMAN: Tonight, December 6, 6:30 p.m. American Legion, $10, Gallatin Valley Snowmobile Association Christmas Party, http://gvsa.net/
BOZEMAN: December 11, 7 p.m., International Mountain Day, Emerson Cultural Center, Avalanche Forecasting and Awareness. http://www.mtavalanche.com/images/13/international-mountain-day
FOUR CORNERS: December 11, 7 p.m., 1-hour Avalanche Awareness for Snowmobilers at the GVSA Groomer Shed, http://gvsa.net/
WEST YELLOWSTONE: Snowmobiler Intro to Avalanches w/ Field Course, West Yellowstone: 19 and 20 December. Info and registration: https://www.ticketriver.com/event/7116