GNFAC Avalanche Forecast for Sun Jan 20, 2013

Not the Current Forecast

Good morning. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Sunday, January 20 at 7:30 a.m. Today’s advisory is sponsored by Gallatin County Search and Rescue and is dedicated to Tyler Stetson was killed in an avalanche while skiing in Beehive Basin on this day in 2008. This advisory does not apply to operating ski areas.

Mountain Weather

A ridge of high pressure off the pacific coast is producing a northwest flow over our area.  Unfortunately, there is little moisture associated with this flow meaning southwest Montana will remain dry today.  Currently, temperatures are in the high teens to low twenties F and winds are blowing 15-25 out of WNW.  Today, temperatures will climb into the upper twenties F to low thirties under partly cloudy skies and winds will remain 15-25 out of the WNW.  No snow is expected over the next 24 hours.

Snowpack and Avalanche Discussion

Bridger Range   Madison Range   Gallatin Range  

Lionhead area near West Yellowstone   Cooke City

Finding fresh powder is becoming more challenging by the day.  Lack of precipitation and strong winds have left very few slopes undisturbed (photo). This has been both a blessing and a curse for stability.  On a positive note, consistent winds have helped to destroy or limit development of surface facets in many areas.  This has allowed recently formed wind drifts to bond well to the old snow surface.  Yesterday, I did a long tour around Hyalite and found generally stable conditions.  Although snow quality was variable, we felt comfortable skinning and skiing most slopes up to 35 degrees.  Doug also found good stability in Cooke City over the past two days.   

While many slopes lack buried weak layers, some continue to harbor faceted snow buried 6-16 inches deep (snowpit1, snowpit2). A good place to trigger an avalanche is where fresh wind slabs rest on this layer.  Yesterday, my partner and I did experience one large collapse on a west facing, mid-elevation slope that was heavily wind loaded. This was the only sign of instability we received all day, but it was enough to make us change our travel plans.   

Fortunately, looking for and assessing this weak layer can be done quickly (video). Digging a few snowpits in the area you plan to ride will help determine if this layer is present.  If buried facets are found, pick a different slope or one less than 35 degrees in steepness.

Today, human triggered avalanches remain possible on wind loaded slopes and slopes steeper than 35 degrees which have a MODERATE avalanche danger.  All other slopes have a LOW avalanche danger.               

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.

Practice using your beacon – The Friends of the Avalanche Center in partnership with the City of Bozeman Recreation Department recently installed a beacon training site at Beall Park. It’s free and easy to use.

Learn from recent accidents – On Monday, a skier triggered and was caught and fully buried in an avalanche near Missoula on a slope with thick trees. He was luckily uninjured and quickly dug out by his partner. Report, photos, video

EDUCATION

Wednesday, Thursday, and Saturday, January 23, 24, and 26.  MSU Introduction to Avalanches with Field Course.  Wed and Thurs evenings and all day Saturday.  For more information and to register, visit: https://www.ticketriver.com/event/4970-introduction-to-avalanches-w--field-course

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