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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Graham Predeger  
Monday, December 17th 2012
Created: Dec 17th 6:49 am
2 Moderate Alpine / Above 2,500' Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
1 Low Treeline / 1,000'-2,500' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
1 Low Below Treeline / Below 1,000' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
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Alyeska Resort
The Bottom Line

The avalanche danger today remains MODERATE with human triggered avalanches possible above treeline.  Our snowpack is still comprised of weak faceted snow overlain by a stiff wind slab at the higher elevations.  These weak facets are still showing reactive to human travel as recently as yesterday on the southwest face of Sunburst.  Below treeline the danger is LOW due to the lack of a cohesive slab.


Primary Concern

The persistent weak layers that make up the lower half of our snowpack are becoming more stubborn to trigger but the very nature of these means they can persist long after any significant wind or precipitation.  All it takes is the right trigger in the wrong spot to unleash a destructive slide.  Keep this in mind as you travel through the mountains today and for the rest of the season, as this weak layer is widespread and likely to be with us for a while.  Below treeline from the ground up, our snowpack is one persistent weak layer (buried surface hoar and facets of varying sizes).  This does not pose a concern until we see significant wind or precipitation at these lower elevations to form an overlying slab.


Secondary Concern

This past weekend our snowpack has proven reactive to a skiers weight with several skier triggered wind slabs both on Tin Can and the SW aspect of Sunburst.  These were all triggered between 2700-3000’ in wind-loaded terrain on west and southwest aspects.  I don’t expect this slab to build much in the coming days given there is very little snow available for transport, but a skier or snowmachiner may still be able to trigger small avalanches in specific areas or large avalanches in isolated areas of big terrain.  Continue to travel through the mountains with heightened concern today and do not disregard the red flags the mountains give us.  Recent avalanches and loud whumphing are two you may expect to see today. 


Mountain Weather

Temperatures have begun to rise from yesterdays sub-zero lows but it'll feel anything but warm in the backcountry today as you can expect a brisk north wind in the 17-35mph range for much of the day.  Tomorrow looks to be our only chance to pick up a few flakes as winds become SE and a weak low pressure moves over Kodiak, but don't expect much as the track appears to be well south of us.  Looking out toward the weekend, models suggest a continuation of cold and dry conditions over southcentral Alaska... Don't shoot the messenger!


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). 

Wendy will issue the next advisory Tuesday morning, December 18th.

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).

Winter snowmachine use open/closed status and riding conditions updates

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: Dec 08, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Closed
Placer River: Closed
Skookum Drainage: Closed
Turnagain Pass: ClosedRain and snow have fallen in Turnagain Pass this week, but not enough to open for snowmachining. Continue to check back to this site for updates.
Twentymile: Closed
Seward District
Carter Lake: Closed
Lost Lake Trail: Closed
Primrose Trail: Closed
Resurrection Pass Trail: ClosedResurrection Pass trail is expected to open to snowmachine use during the 2017/18 winter season.
Snug Harbor: Closed
South Fork Snow River Corridor: Closed
Summit Lake: Closed

Subscribe to the Turnagain Area Avalanche Advisory:

The information in this advisory is from the U.S. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur. This advisory provided by the Chugach National Forest, in partnership with Friends of the Chugach National Forest Avalanche Information Center.


USFS SNOW AND AVALANCHE HOTLINE (907) 754-2369
If you have comments or questions regarding CNFAIC operations or winter recreation management, please email staff@chugachavalanche.org
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