Special Northwest Montana Backcountry Avalanche Bulletin – Dec. 29, 2011
For the Glacier Park and Flathead and Kootenai National Forest areas
by Tony Willits, U.S. Forest Service
December 29, 2011
Special backcountry avalanche bulletin issued by the U.S. Forest Service at 1400 Thursday, December 29th, 2011, for the Glacier Park and Flathead and Kootenai National Forest areas.
HAZARD ANALYSIS
Between the elevations of 5,000 and 7,500 ft. the avalanche danger is currently rated HIGH on all steep and open wind loaded terrain from new storm accumulations and wind loading. This advisory is addressing strong overnight winds Wednesday and early Thursday morning. New snow and wind transported snow is causing natural and triggered avalanches on E, NW, N, & NE slopes at or near ridge tops, although could be triggered on all aspects near ridge tops with terrain influences. These hazardous conditions are exasperated by a heavy more dense snow overlying a less dense shallow colder snow pack These avalanche sizes are running moderate to large and some have fractures depths up to 2 to 3 foot in depth, with some stepping down to bear grass.
This danger rating expires at midnight, Thursday, December 29th, 2011. New snow and moderate to strong westerly winds will further overload and stress the current snow pack tonight so please stay tuned to tomorrow’s advisory issued prior to 0800 Friday, December 30.
Because of the general nature of this advisory message, each backcountry party will always need to make their own time and site specific avalanche hazard evaluations. This advisory best describes conditions at the time of its issuance. As time passes avalanche and snow conditions may change, sometimes quite rapidly. Elevation and geographic distinctions used are approximate and transition zones between hazards exist.
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