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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Kevin Wright  
Wednesday, March 12th 2014
Created: Mar 12th 6:51 am
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.
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The Bottom Line

With 22+ inches of storm snow yesterday morning, in addition to 4 inches in the last 24 hours we are still adapting to the new load.  Yesterday we witnessed small avalanches break in small terrain and one larger slide remotely trigger in steep terrain (with skiers approaching from a safe area).  

Today is all about giving the snowpack time to settle, bond, and adjust.  Dangerous avalanche conditions will be found without a lot of searching.  CONSIDERABLE danger will be found both above and below treeline, on all aspects.  Today is a great day to stay on lower angle slopes and enjoy the new snow in mellow terrain.  


Primary Concern

The storm snow that makes up our primary concern started falling on Monday.  It tapered off substantially yesterday and transitioned to rain below 1000 feet.  All told, more than 2 feet of new snow fell from this storm.  Combined with a lot of wind, we have scoured areas between heavy wind loading.  

Yesterday we were finding the storm snow would break easily on the new snow/old snow interface.  This is the old surface layer about an inch above the late February crust.  This is a very easy interface to identify, no need to pull out the shovel, just dig in with your hand to find it.  Any avalanches today are likely to break a little above that crust, taking 2 feet of storm snow or greater amounts in wind loaded areas.  Areas with now buried surface hoar may behave even worse with a persistent weak layer involved.

I'll mention that avalanche activity yesterday seemed a bit sluggish - initiation was slow and avalanches were somewhat small in size for the amount of snow we got.  This doesn't mean much in terms of travel advice...  It's still an easy call when managing today's problem.  A lot of new snow on top of a crust with sporadic buried surface hoar - requires conservative travel in the backcountry.  


Secondary Concern

Below 1000 feet we did get rain at the later half of this storm.  The lower you go, the more rain we got.  This isn't a big concern, just keep in mind that lower elevations have a water saturated surface layer.


Mountain Weather

The recent storm is the big news.  Storm totals listed below.  Numbers are 48 hour snow totals.  Keep in mind that the snow is settling and temperatures increased during the storm, transitioning to rain at lower elevations.

Girdwood midway - 26"  (2.25" water equivalent)

Turnagain Pass - Center Ridge - 25" (2.2" water equivalent)

Summit Lake - 12" (1" water equivalent)

Wind blew hard during the peak of the storm, which caused visually evident scouring of ridges.  Max gusts were recorded up to 114mph at ridge tops.  That wind diminished yesterday.

Today will bring a short break in precipitation intensity.  Snow and rain showers are expected throughout the day with an inch of accumulation.  Wind is increasing through the day as another weather front approaches.  

Tonight and tomorrow will bring another storm similar to the last one.  Predicted snow totals for tonight and Thursday are 14-24 inches.  There is a high wind warning in effect 2am to 8am Thursday for Turnagain Arm and Portage.

 

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: May 16, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Closed
Placer River: Closed
Skookum Drainage: Closed
Turnagain Pass: ClosedThanks all for a safe and fun season on the Chugach NF! Stay tuned for the 2017/18 season. #playsafe #snowtosealevel
Twentymile: Closed
Seward District
Carter Lake: Closed
Lost Lake Trail: Closed
Primrose Trail: Closed
Resurrection Pass Trail: ClosedResurrection Pass trail will be open to snowmachine use during the 2017/18 winter season.
Snug Harbor: Closed
South Fork Snow River Corridor: Closed
Summit Lake: Closed

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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.


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