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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Kevin Wright  
Thursday, February 20th 2014
Created: Feb 20th 7:02 am
3 Considerable Alpine / Above 2,500' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
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.
 Show the Complete North American Avalanche Danger Scale
Alaska Alpine Adventures LLC
Special Announcement

All motorized areas in Chugach National Forest are OPEN!  


The Bottom Line

In the past 24 hours we have not heard of any new avalanche activity.  However, the well documented weak layer above the January crust is still demonstrating problems.  

MODERATE avalanche danger is widespread across our forecast zone.  Careful terrain management is still warranted because of the known weak layer.  Natural avalanches will be unlikely today, human triggered avalanches are very possible in areas with steeper terrain.  The depth of potential avalanches is getting to be significant - 3 feet or more in wind loaded areas.  

Specific areas of CONSIDERABLE danger may still be present where the last storm deposited the most snow (Girdwood valley and other locations).  In these areas human triggered avalanches may be likely and careful terrain management is essential.

We cannot forget all the skier triggered avalanche activity that's happened in the last 2 weeks.  More snow has buried the weak layer deeper, apparently making triggering less likely.  Consequences of triggering will be greater with deeper and possibly wider avalanches when somebody finds the trigger point.  


Primary Concern

The faceted weak layer on top of the January melt/freeze crust is definitely the most concerning part of the snowpack.  It has been responsible for widespread collapsing and avalanche activity over the last 2 weeks.  

The sensitivity of this weak layer seems to be waning, but probably because it is now buried more than 2 feet in most places, and over 3 feet in some wind loaded areas.  With that much snow insulating the problem layer, triggering will be more difficult.  

This problem needs to be considered when you venture onto steeper terrain today.  Consider the consequences of the slope releasing and the terrain in the runout below.  

Crystal card grid is 3mm spacing.  These facets produced an ECTP 14 - propagation under a moderate force.  Location - Sunburst, south aspect, ~3200 feet.


Mountain Weather

The last snowfall was 2 days ago.  Storm totals varied widely depending on location.  The upper mountain of Alyeska received 22 inches, while Turnagain pass only had about 2 inches.  Snowfall at Turnagain pass since February 7th has been 51 inches!

Weather yesterday partly cleared in the afternoon.  Wind has been light since the last snowfall ended.  Temperatures remain cold with single digits at ridgetop stations and teens at sea level.  

A clearing trend is expected today.  Partly cloudy in the morning and mostly sunny in the afternoon.  Expect a north to west wind 10-20mph.  High temperatures in the mid 20s.  

 

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
If you have comments or questions regarding CNFAIC operations or winter recreation management, please email staff@chugachavalanche.org
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