GNFAC Avalanche Advisory for Wed Jan 14, 2015

Not the Current Forecast

Good morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Wednesday, January 14, at 7:30 a.m. Today’s advisory is sponsored by Mystery Ranch in partnership with the Friends of the Avalanche Center. This advisory does not apply to operating ski areas.

Mountain Weather

Like yesterday, today will be sunny but a little warmer. Currently mountain temperatures are in the high teens to low 20s. Winds are westerly and blowing 20-30 mph in the Bridger Range and Hyalite and 10-20 mph everywhere else. Winds will remain the same and temperatures are expected to rise into the low 30s as high pressure continues to dominate our weather.

Snowpack and Avalanche Discussion

Bridger Range   

Strong winds blew snow around in the Bridger Range yesterday creating wind slabs that were easily triggered. Sunday’s eight inches of new snow has been packed into soft slabs that are breaking 8-14 inches deep. People triggered many wind slabs in the northern part of the range, most notably around Fairy Lake and Frazier Basins. A sizeable avalanche was seen immediately to the south of Fairy Lake which is a reminder that some slopes have deeper instabilities. Winds have not abated and there are many slabs of windblown snow that you can trigger. Today the avalanche danger is rated CONSIDERABLE on wind-loaded slopes and MODERATE elsewhere.

Gallatin Range   Madison Range   Lionhead area near West Yellowstone   

Without new snow or significant wind loading, the mountain ranges from Bozeman to Big Sky and West Yellowstone are trending towards strength and stability. Trending should not be confused with arriving. Two weak layers continue to be on my mind: facets near the ground and surface hoar buried 1.5 feet deep. A snowmobiler in Taylor Fork of the southern Madison Range found small natural slab avalanches breaking at the ground from Sunday’s snowfall (photo). Mark found this layer underneath three feet of snow around Lionhead where it was showing signs of instability in his snowpits (video). The second weak layer, surface hoar, is shallowly buried and can be revealed with a few scoops of a shovel. It will appear as a stripe in the pit wall. Once found it’s worth doing a quick extended column test to see if it’s reactive, and if so stay off steep terrain. Given the possibility of triggering a slide along with the need to carefully evaluate the snowpack, today’s avalanche danger is rated MODERATE.

Cooke City

The snowpack around Cooke City is behaving nicely, a change of pace from its usual unruly nature. A few small avalanches were triggered last Wednesday and Thursday (photo) as a layer of surface hoar broke two feet deep under the weight of the new snow. On Monday, I rode around and dug many snowpits searching for and testing this layer (photo). Its distribution and instability is sporadic, but if found a rider or skier could still trigger an avalanche on a steep slope. For today, the avalanche danger is rated MODERATE on all slopes steeper than 35 degrees and LOW on less steep terrain.

Mark 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.

TONIGHT: 1-hour Avalanche Awareness, 4 Corners, 7 p.m., Wednesday, January 14, GVSA Groomer Shed.

TONIGHT: 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

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