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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Kevin Wright  
Thursday, February 13th 2014
Created: Feb 13th 6:59 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
The John Byrne Family
Special Announcement

There are still a few raffle tickets left for the February 21st drawing! Prizes include a day of Heli Skiing with Valdez Heli-Ski Guides and Alaska Airlines tickets among other great prizes from our sponsors! You can catch up with the Friends of the Chugach National Forest Avalanche Information Center at the Midnight Sun Brewing Company after 6PM this Friday and Sunday (14th and 16th) to pick up your ticket AND free swag!


The Bottom Line

A few inches of new snow since yesterday will improve the already nice surface conditions around Turnagain pass.  

The main avalanche issues are holding steady - Below 3000 feet the soft snow may slide on a faceted layer above the prominent crust.  Above 3000 feet the soft snow may be stiffer and slabbier, but the presence of a weak interface is less common with the absence of the crust.  

MODERATE danger is present in areas where wind has built cohesive slabby conditions above treeline.  Below treeline is LOW avalanche danger.


Primary Concern

By far the most common problem is related to recent snow on top of the prominent crust layer.  The 16+ inches that Turnagain Pass received on February 7th have been responsible for many reported avalanches since that storm.  The general trend of these avalanches is - small in size (12-20" deep), lower volume, decent propagation across wind stiffened steep slopes.  Check out the observations page for a bunch of photos from the last 6 days, and this observation for a good quick synopsis of the problem.  

The 2 properties necessary to create avalanches that are not always found -

1.  A cohesive slab - some wind loading and stiffening is necessary to create connectivity of the surface snow, otherwise it's just loose powder with sluff potential.

2.  A faceted interface between the new snow (Feb 7th storm) and the underlying crust (January melt/freeze) or old snow.  In places where the facets are present, this is a significant weak layer consisting of large loose grains with poor bonding.  

 


Mountain Weather

Cold high pressure from early in the week has transitioned to a showery precipitation pattern as of yesterday afternoon.  A few inches of fresh light powder have fallen since Wednesday.  Temperatures remain quite cold, especially for snow to be falling, reaching into the negatives at many of our local weather stations.  Wind is generally light, although since about 4am the wind has increased slightly and switched over to a East Northeast direction.  Expect cloudy skies today with snow showers and 2-4 inches of snow accumulation today.

The extended forecast looks like more of this same pattern.  A low pressure system is anchored over the northwestern gulf, and expected to stay there well into next week.  Most precipitation from this event will be showery, but there is a chance for heavier snow events by the weekend.  

 

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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