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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Kevin Wright  
Saturday, March 22nd 2014
Created: Mar 22nd 6:44 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.
 Show the Complete North American Avalanche Danger Scale
Tesoro Foundation
Special Announcement

Come join CNFAIC forecasters this Sunday for a FREE AVALANCHE RESCUE WORKSHOP at Turnagain Pass!  Focus will be on beacon practice through avalanche rescue scenarios.  We’ll meet in the motorized lot at 10:30am and wrap up by 1:30pm.  Skiers and sledders welcome!  Please drop a note to kevin@chugachavalanche.org to reserve a spot for you and your crew, as space is limited.


The Bottom Line

Confidence in the overall stability of our snowpack is increasing each day.  It has been a full week since the end of the last storm.  Since then we saw a typical rash of avalanches immediately following the storm.  The last few days people have really started skiing on steep terrain, without triggering the deep slab that has concerned us.    

Overall, we are starting to feel pretty good about our stability, but a twinge of doubt for the possibiltity of triggering a deep slab in steep complex terrain is preventing a low danger rating for now.  Our current stability is good, but it's not as good as it can get.
 
A MODERATE danger can be found in some areas above treeline in steep terrain >35 degrees for deep persistent slab and wind slab.  Everywhere else the danger is LOW.

Primary Concern

This problem is increasingly becoming unlikely, but the hazard associated with it could be dangerous if triggered.  The storm snow from last week has now settled to about 3+ feet of hard consolidated snow.  This slab is strong and difficult to trigger, but it sits at an interface that sometimes shows poor bonding to the older layer below it.  

The deep slab is most likely to be triggered from a shallow area where the slab tapers down to 1 foot deep or less.  Alternatively a large trigger like multiple skiers or a snowmachine could initiate through a deeper portion of the slab.  

Photo - Typical steep terrain with deep slab avalanches evident from the storm and large cornice features.


Secondary Concern

We got a report of a small wind slab triggered in Pastoral a couple days ago.  Click here for observation.  An east wind was loading up westerly aspects.  Today it is possible to find stiff aging wind slab that could pop when traveled on.  Keep this in mind, especially in steeper terrain.


Additional Concern

Cornices are big and mature this time of year.  As people get onto steeper terrain the cornice factor becomes more significant.  In some steep areas they are a mandatory nuisance to be negotiated.

Remember to scope out a safe entrance that avoids a blind approach onto overhanging cornice features.  Take a rope for a safe belay if you think your chosen line can't avoid cornice exposure.  


Mountain Weather

The last storm ended more than a week ago.  High pressure and sunny skies have dominated the weather pattern since then.  We had some moderate wind on Thursday that blew some snow around.

We are looking at another calm sunny day ahead of us.  Temperatures will start out cold this morning, ~10 degrees at valley floor and ~20 degrees at the ridgetops.  The sun will quickly warm things up to the high 30s in the afternoon.  East wind to 10mph.

Sun will stay in the forecast into mid week.  No major storms are on the horizon as the Rex block continues to dominate weather over Alaska.

 

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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