GNFAC Avalanche Advisory for Fri Feb 6, 2015

Not the Current Forecast

Good morning. This is Mark Staples with the Gallatin National Forest Avalanche Advisory issued on Friday, February 6, at 7:30 a.m. A Montana FWP Recreation Trails Grant sponsors today’s advisory. This advisory does not apply to operating ski areas.

Mountain Weather

Warm and windy! This morning mountain temperatures ranged from 30 to 40 degrees F with the base area at Bridger Bowl at 48 degrees F. Winds were averaging 20-40 mph and gusting 50-60 mph from the SW. Yesterday at Big Sky winds reached 85 mph in one location. Today will be a mix of sun and clouds with high temperatures approaching 50 degrees F near Bozeman and 40 degrees F in most other places. Strong SW winds will continue today. By tomorrow morning the southern half of the advisory area should get 2-3 inches of snow with more falling during the day on Saturday.

Snowpack and Avalanche Discussion

Wet Snow Avalanche Danger

Temperatures this morning were at or above freezing and expected to rise today. With new snow in most areas, it will only take a little bit of direct sunshine to cause loose, wet snow avalanches. These will be a serious problem for ice climbers. Check out this video from late January in Hyalite Canyon when we had sun and similarly warm tempertures. Today the wet snow avalanche danger could rise to CONSIDERABLE on south aspects especially near rock faces and in gullies.

Bridger Range   Madison Range   Gallatin Range  

Lionhead area near West Yellowstone   Cooke City

Wind slabs are the primary avalanche problem today (wind video). Unusually warm temperatures should help them bond to the underlying snow and be less sensitive but strong winds will continue loading slopes today. Yesterday near Cooke City, Eric and his partner triggered a small wind slab (photo), and my partners and I found a small wind slab that had released naturally near Buck Ridge just south of Big Sky (photo).

Before last weekend, many places had a layer of surface hoar crystals on top of the snow. This layer is buried in some areas as Doug found on Lionhead near West Yellowstone (video, photo). I saw this layer on Buck Ridge last weekend, but couldn’t find it under the new snow yesterday and my partners and I confidently ripped stable powder on steep, non-wind loaded slopes. Eric and his partner couldn’t find buried surface hoar near Cooke City (video), and a regular observer in that area didn’t find it either. This layer does not exist in the Bridger Range.

Watch for and avoid fresh wind slabs. Also look for buried surface hoar and avoid slopes that have it because it is a notorious weak layer that surprises many avalanche professionals. This task is easy because you only need to dig 1-2 feet deep (make sure to cut a smooth wall in the snow) and look for a stripe in the snow. Today with continued strong winds the avalanche danger is rated CONSIDERABLE on wind loaded slopes and MODERATE on all others.

AN ARTICLE FOR PARENTS

Are you a parent of a kid that skis at a ski area? Do you know if they head out-of-bounds into the sidecountry? Doug’s article “Sidecountry”: Rated R sheds light onto the seriousness of skiing the uncontrolled and unpatrolled slopes next to a ski area.

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.

KING AND QUEEN OF THE RIDGE

Saturday, February 14th is the 13th Annual King and Queen of the Ridge Hike/Ski-a-thon fundraiser at Bridger Bowl to support avalanche education in southwest Montana. Collect pledges for each lap of hiking to the ridge and skiing back down. 100% of the proceeds go to the Friends of Gallatin National Forest Avalanche Center. Hike as an individual or form a team of your workmates or playmates or family! Prizes are awarded for Team and Individual categories. Make a Pledge. Sign Up and More Info.

AVALANCHE EDUCATION and EVENTS

Take a look at our Education Calendar for all classes being offered.

Woman's 1-hour Avalanche Awareness, Bozeman, REI, 6:30 p.m., Wednesday, February 11.

Companion Rescue Clinic, Bozeman, REI, 6-8 p.m., Friday, February 20 and 10 a.m.-2 p.m. on Saturday, February 21 (field location TBD). Pre-registration is required: www.rei.com/stores/bozeman.html

1-hour Avalanche Awareness, West Yellowstone, Holiday Inn, 7 p.m., Saturday, February 21.

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