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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Kevin Wright  
Thursday, December 12th 2013
Created: Dec 12th 6:34 am
1 Low Alpine / Above 2,500' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
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 Bottom Line

Avalanche danger is currently LOW in our region.  The big change in the last couple days is a dramatic drop in temperatures, with a change from above freezing to below freezing.  That action typically "locks" the snowpack in place until another change occurs.  


Primary Concern

There is still visible evidence of loose snow "avalanche" activity from the last week.  In every case we've seen these have been low-volume point releases that occurred during the warm temperatures.  

Now, as temperatures have plummeted, a prominent melt/freeze ice crust should be expected everywhere on the snow surface.  This crust will be found at all elevations and all aspects.  It formed from freezing rain and above freezing temperatures between Dec 2-8.  We haven't seen this crust to be strong enough to be supportable anywhere - the underlying snow is just too weak to provide strength under the crust.  This makes for very challenging mountain travel right now. 

That crust also has a surface hoar layer forming, adding to the complexity of our future bed surface.

Photo - Bob Sutherland - crust with surface hoar


Mountain Weather

The temperature profile above is from the Seattle ridge weather station, showing a timeline from Dec 8 to the present.  This is the reason why we have the melt/freeze crust everywhere.  Current temperatures range from low single digits to the teens at some sea level locations.  

It hasn't snowed in quite a while, making temperature swings and freezing rain the most interesting weather events over the last week.

The forecast discussion for Friday and Saturday is exciting!  "The upper air pattern shift is complete... and a surface low tracking into then stalling in Prince William Sound."  "The bulk of accumulating snow comes Friday and Early Saturday.  Storm total accumulations for Anchorage and vicinity will generally range from 4 to 8 inches... but there is the potential for locally higher values."

Read the entire discussion HERE.  We can expect our snowpack stability to get dramatically worse with this new snowfall for the weekend, depending on how much we get.  Stay tuned and check back for the latest information.

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: Apr 28, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Closed
Placer River: Closed
Skookum Drainage: ClosedSKOOKUM DRAINAGE CLOSED TO MOTORIZED USE ON APRIL 1 annually as per the Chugach National Forest Plan document.
Turnagain Pass: OpenOpen thru May 14th.
Twentymile: Closed
Seward District
Carter Lake: OpenClosed May 1.
Lost Lake Trail: OpenClosed May 1.
Primrose Trail: OpenClosed May 1.
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: OpenClosed May 1.
South Fork Snow River Corridor: OpenClosed May 1.
Summit Lake: OpenClosed May 1.

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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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