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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Kevin Wright  
Saturday, December 14th 2013
Created: Dec 14th 6:45 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.
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.
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The Bottom Line

New storm snow falling on a slick rain crust is increasing the avalanche danger.  With only a moderate amount of snow from this storm, I expect only MODERATE avalanche danger.  However, confidence is low in this forecast until we are able to get into the field to verify the assessment.  

The interface of new snow on the ubiquitous crust is expected to provide poor bonding and low friction, meaning the new snow will not stick well and will slide off easily.  We also had sporadic surface hoar on top of the crust in some areas.  This unusual situation may make the avalanche conditions more dangerous than normal for a storm this size.

Natural and human triggered avalanches will be possible today in wind loaded areas, but are expected to be small in size and low volume.


Primary Concern

Given a relatively small amount of snow from this storm, I don't think storm slabs will be widespread without a wind loading component.  Areas with deeper deposition due to wind - higher elevation, near ridgetops - will be the primary avalanche concern.  

Sunburst weather station recorded a gust to 43 mph this morning.  The light weight, low density snow will be easily and quickly moved around by wind.  


Secondary Concern

Areas unaffected by wind may have a tendency to form loose snow avalanches.  I expect any sluffs to be low volume and low force due to the cold, light density nature of this storm.

 


Mountain Weather

Yesterday the snowfall started in the morning.  Temperatures have risen a little bit, but remain well below freezing in all locations.  Ridgetop wind has also been increasing since yesterday, with gusts reaching into the 30s and 40s from the East.

Snowfall accumulation up to this point is around 6-8 inches near treeline with more expected up higher.  Water content is low from the cold temperatures - this is light density powder.  

Today's forecasted weather is continued snow showers, with less precipitation intensity than we had overnight.  A second round of snow will commence later this afternoon into the evening.  The storm is expected to taper off by late Sunday morning.  When it's all said and done, storm totals may reach more than a foot of snow in some places.  

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.


USFS SNOW AND AVALANCHE HOTLINE (907) 754-2369
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