GNFAC Avalanche Advisory for Fri Dec 23, 2011

Not the Current Forecast

Good morning. This is Mark Staples with the Gallatin National Forest Avalanche Advisory issued on Friday, December 23 at 7:30 a.m.  This advisory is sponsored by Alpine Orthopedics and Javaman in partnership with the Friends of the Avalanche Center.  This advisory does not apply to operating ski areas.

Mountain Weather

Yesterday was beautiful and clear but winds increased in the afternoon. This morning on ridgetops at Bridger Bowl and Hyalite Canyon winds were blowing 25-30 mph with gusts 40-50 mph from the W and NW. In other areas winds were blowing 15 mph gusting to 30 mph. Temperatures this morning were in the teens F and will climb into the 20s F today. Winds will remain strong generally blowing 15-30 from the NW; however, some downslope winds will occur today. It looks like the boys and girls of SW Montana have been bad this year and will not get any snow for Christmas. Instead of coal in our stockings, it looks like we’ll get a good dose of wind.

Snowpack and Avalanche Discussion

The Bridger, Gallatin and Madison Ranges, the Lionhead area near West Yellowstone and mountains around Cooke City:

Weak snow continues to plague much of SW Montana, but finding avalanches today will require finding wind loaded slopes. Recent winds scoured many slopes typically wind loaded and blew snow onto others that are typically not. Additionally, increased winds today may start loading some slopes not at the top but further down, mid-path.

Yesterday on Lionhead, Doug and Eric found many E-facing avalanche starting zones scoured of all the new snow. They were able to see Eric’s snowpits from nearly 1 month ago. The snowpack near West Yellowstone has weakened everyday during that time (photo, video). Further north, recent snowfall dodged the Bridger Range but winds have not. In that area wind slabs may not as large as in other areas, but they should fracture just as easily.

In Hyalite Canyon yesterday I was fortunate to ski with two experienced, avalanche professionals. We experienced no collapsing or cracking, and from the top of Palace Butte could only find 1 recent natural avalanche (photo). Other parties in the area reported similar findings, and these reports are promising given the heavy load of new snow.  The Hyalite area has received more snow than other areas and has a stronger snowpack than other areas (snowpit). It is slowly earning my trust, but we remained cautious as this snowfall was the first big test for this snowpack. Yesterday winds were confined to ridgetops (photo) but today they should affect more areas and keep the avalanche danger elevated. Cooke City has a similar snowpack. 

Although the snow storm ended Wednesday, the “wind storm” began yesterday afternoon. Some natural avalanches should occur on wind loaded slopes, and human triggered avalanches will be likely on these slopes. For today a CONSIDERABLE avalanche danger exists on all wind loaded slopes. With a generally weak snowpack and a good dose of new snow, avalanches are definitely possible on slopes not affected by the wind where a MODERATE avalanche danger exists.

Eric 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 

To check out all our education programs: http://www.mtavalanche.com/workshops/calendar

BOZEMAN

Women’s 1-hour Avalanche Awareness Lecture. Wednesday, January 4, 6:30- 8 p.m. at REI.

Snowmobiler Introduction to Avalanches with Field Course. Lectures on Saturday, January 7, with an all day field session Sunday, January 8. Advanced registration IS REQUIRED.

1-hr Avalanche Awareness Lecture. Wednesday, January 11, 6:30-7:30 p.m at REI.

BIG TIMBER

1-hr Avalanche Awareness Lecture. Tuesday, January 10, 7-8 p.m at Big Timber High School.

HELENA

1-hr Avalanche Awareness Lecture. Thursday, January 12, 6:30-8:30 p.m at Exploration Works.

CODY, WYOMING

Snowmobiler Introduction to Avalanches with Field Course. Lectures on Saturday, January 14 at Mountain Valley Motorsports with an all day field session near Cooke City on Sunday, January 15. Advanced registration IS REQUIRED.

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