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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Graham Predeger  
Friday, December 7th 2012
Created: Dec 7th 6:43 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.
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The Hoarding Marmot
The Bottom Line

The avalanche danger remains MODERATE today above treeline due to the potential for skiers to trigger wind slabs specifically on slopes steeper than 35 degrees.  Natural avalanches are unlikely today at all elevations and the avalanche danger will remain LOW below treeline. 

A major shift in our weather pattern this weekend has the potential to stress our snowpack and complicate our avalanche problem in the Turnagain area, so stay tuned!


Primary Concern

Much of our snow cover from the valley bottom to ridge tops consists of weak, unconsolidated facets in one form or another.  This is the type of snow you can’t make a snowball out of to save your life.  You may be able to find pockets of more consolidated snow (wind slabs) on the lee sides of ridges and gullies above treeline, but these too have a foundation of weak facets creating a very poor snowpack structure.  It should be quite obvious today if you venture onto a slab as it’ll have a hollow, supportive feel to it.  This surface will feel very different from the last several thousand feet of “sugar snow” you just ski-toured up through.  These wind slab pockets are the primary concern today and triggering one will likely result in a full depth avalanche running to the valley floor.  With a shallow, faceted snowpack consequences of triggering one of these wind slabs may leave you broken and battered if caught.

It’ll be important today to understand and come to grips with what our seasonal snowpack looks like to date as this weekend looks to be ushering in our first real winter storm of the season.  What snow we have on the ground now will soon be buried and act as a foundation for the rest of the season.  Expect our avalanche problems and associated danger rating to change with this impending storm.


Mountain Weather

A change in our weather pattern of the last several weeks has begun as the cold arctic air mass that has dominated the south central region begins to break down.  We still have a temperature inversion between sea level (0 degrees in Portage) and 3800’ (15 degrees at Sunburst weather station) but expect this to break down by tomorrow morning as well.  Today will be a transition day where we can expect ridgetop winds to shift from a west-northwest direction to more east-southeast as a low pressure system in the gulf builds in strength and enters our forecast area late tonight or Saturday morning.  Cloud cover in the Turnagain pass region will build today with this approaching front with a few flurries possible by this afternoon.


The bulk of this approaching storm will impact our area Saturday afternoon through Sunday.  The eastern Kenai Peninsula looks to be favored with models suggesting 12-24” of snow in localized areas (1-2” of water equivalent).  Expect blizzard conditions all day Saturday as winds associated with this storm are forecast to be 30-45mph from the east, likely higher at ridge top locations. 


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). 

Kevin will issue the next advisory Saturday morning, December 8th.

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: Mar 28, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: OpenPlease park on road in and leave the turnaround (near outhouse) open for trailers to turn around.
Placer River: OpenPlacer remains open but SKOOKUM DRAINAGE will close to motorized use on April 1st.
Skookum Drainage: OpenSKOOKUM DRAINAGE CLOSES TO MOTORIZED USE ON APRIL 1 annually as per the Chugach National Forest Plan document.
Turnagain Pass: Open
Twentymile: Open
Seward District
Carter Lake: Open
Lost Lake Trail: OpenPlease STAY ON existing and hardened trail surface through the lower sections of this route.
Primrose Trail: OpenPlease STAY ON existing and hardened trail surface through the lower sections of this route.
Resurrection Pass Trail: ClosedClosed for 2016/17 winter season. This is a non-motorized season. This alternates every other year and will open again during the 2017/18 winter.
Snug Harbor: Open
South Fork Snow River Corridor: Open
Summit Lake: Open

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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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