Avalanche Advisory

Turnagain Area Avalanche Advisory Saturday, December 21st 2013 6:26 am by Kevin Wright ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.

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Human triggered avalanches have been reported in the last 24 hours.  The most significant that we know of is this report from Summit.  Snowpack structure remains poor, and red flags such as whoomphing are common if you break trail.  

The danger rating is MODERATE for persistent slab concerns, especially in areas that have a stiffer wind slab on the surface.  Natural avalanches are unlikely but human triggered avalanches are possible in steep terrain.  

Show the Complete North American Avalanche Danger Scale

North American Public Avalanche Danger Scale Avalanche danger is determined by the likelihood, size and distribution of avalanches. Danger Level Travel Advice Likelihood of Avalanches Avalanche Size and Distribution 5 Extreme Avoid all avalanche terrain. Natural and human- triggered avalanches certain. Large to very large avalanches in many areas. 4 High Very dangerous avalanche conditions. Travel in avalanche terrain not recommended. Natural avalanches likely; human- triggered avalanches very likely. Large avalanches in many areas; or very large avalanches in specific areas. 3 Considerable Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential. Natural avalanches possible; human- triggered avalanches likely. Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas. 2 Moderate Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern. Natural avalanches unlikely; human- triggered avalanches possible. Small avalanches in specific areas; or large avalanches in isolated areas. 1 Low Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features. Natural and human- triggered avalanches unlikely. Small avalanches in isolated areas or extreme terrain. Safe backcountry travel requires training and experience. You control your own risk by choosing where, when and how you travel.

2 Moderate Alpine / Above 2,500'

Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

2 Moderate Treeline / 1,000'-2,500'

Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

2 Moderate Below Treeline / Below 1,000'

Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

Happy solstice!  Our daylight hours will be GAINING from now on.

Avalanche Problem 1

The interface that we have found most likely to fail is around the early December freezing-drizzle crust.  This layer is now buried 12-18 inches or deeper in wind loaded areas.  See this observation for a pit profile.  Every new bit of snow adds stress to those layers, but we haven't had any large storms to overload the snowpack to widespread failure - meaning no large natural avalanche cycle.  This leaves some areas on the brink of failure, waiting for a trigger to release that energy.  A lot of people have noticed widespread whoomphing as the layers collapse when a person walks or rides on the snow.  In a few cases the slope was steep enough to avalanche when that collapse happened.  

A small amount of new snow today will add to the stress in the snowpack, but probably not enough to cause natural avalanches.  The overall avalanche problem today will be similar to the last few days.  

Photos from Tenderfoot, above Summit Lake from Friday.

A little bit of snow fell overnight.  About 2 inches of new are on the ground as of 6am.  A moderate east wind has been steady through the night, gusting to a peak of 27 at Sunburst.  

Another 2 inches of snow is expected to fall through the day today.  Temperatures are approaching freezing, and may pass that mark at lower elevations.  A freezing rain advisory is in effect, mainly in the interior Kenai from Turnagain pass to Moose pass.  

This is a general backcountry avalanche advisory issued for Turnagain Arm with Turnagain Pass as the core advisory area (this advisory does not apply to highways, railroads, or operating ski areas).

Riding status is not associated with avalanche danger. An area will be open to motorized use in accordance to the Forest Management Plan when snow coverage is adequate to protect underlying vegetation. Backcountry hazards including avalanche hazard are always present regardless of the open status of motorized use areas.

(Updated: Apr 22, 2018 )

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