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Avalanche Advisory

Turnagain Area Avalanche Advisory
Thursday, February 27th 2014 6:35 am by Kevin Wright
ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.
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The Bottom Line

Temperatures have continued to rise since yesterday, and rain is predicted to reach 4700 feet today.  This degree of warmup and rain on snow is always a destabilizing factor in the snowpack.  Forecasting the degree of instability or the timing of when natural avalanches may begin is very difficult.  

Confidence in the danger rating is poor, but we may see CONSIDERABLE avalanche danger as a direct result of the warmup and rain.  All elevations and all aspects are suspect today.  Avalanche size and depth potential is speculation until we start seeing how the snowpack reacts to this abnormally warm weather.  


 Show the Complete North American Avalanche Danger Scale
3 Considerable Alpine / Above 2,500' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
3 Considerable Treeline / 1,000'-2,500' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
3 Considerable Below Treeline / Below 1,000' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
Avalanche Problem 1

As the surface snow gets wetter today it adds stress to the snowpack and may decrease snowpack strength.  Wet type avalanches may occur at either low or high elevations.  They could occur naturally or be human triggered.  

Wet avalanches may be confined to the surface layers or they could step down into deeper persistent layers.  


Avalanche Problem 2

The layer of weak facets that sits just above the stout January melt/freeze crust continues to be a concern.  There have been quite a few medium size avalanches reported on this layer over the last 2 weeks.  The most recent we know of was on the 23rd.  Read up on that here.  

 Check out this observation from Eddies on Tuesday to get a sense of the layering.  

In general, the facet layer is now 2-3 feet deep.  It continues to fail with moderate force in snow pit tests, and it will propagate.  The best advice to manage this weak layer is avoiding exposure to steep terrain.


Mountain Weather

Temperatures rose above freezing yesterday, and continue to climb today.  Rain also started yesterday along with periods of strong wind from the Southeast.

Today, some areas are already reaching into the mid 40s F.  Rain will reach the top of most peaks in our forecast zone.  Since yesterday Center Ridge weather station has lost 3 inches of snow depth due to the warmup.

This storm system is focusing precipitation on the southeast Kenai peninsula.  Some spillover moisture is reaching into the Grandview/Spencer and Portage areas.  Turnagain Pass, Girdwood and Turnagain Arm have only gotten a small amount of rain so far and should only get a small amount today.  Look for SE wind 15-30mph through today.

When this storm system passes by Friday afternoon we can expect clearer skies and colder temperatures into the weekend.

 

Temperature graph from Seattle ridge weather station, ending at 6am today.

 

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 01, 2018 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: ClosedClosed
Placer River: ClosedClosed
Skookum Drainage: ClosedClosed
Turnagain Pass: ClosedClosed November 21 due to inadequate snow conditions. #hopeforsnow
Twentymile: ClosedClosed
Seward District
Carter Lake: ClosedClosed
Lost Lake Trail: ClosedClosed
Primrose Trail: ClosedClosed
Resurrection Pass Trail: ClosedClosed for the 2018/19 season. Next season will be open to motorized use.
Snug Harbor: ClosedClosed
South Fork Snow River Corridor: ClosedClosed
Summit Lake: ClosedClosed

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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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