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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Kevin Wright  
Friday, March 1st 2013
Created: Mar 1st 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.
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.
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The Bottom Line

Still within 48 hours of a significant storm event, caution is warranted in the backcountry.  Some areas received over 2 feet of snow in the latest storm.  A handful of large and destructive avalanches were caused by this storm in the last few days.  Above treeline the danger will be MODERATE for storm snow, wind slab, and cornices. 

The backcountry stability is on a steady improving trend.  Natural avalanches are unlikely, human triggered avalanches are possible in specific steeper terrain. 

Watch for lower elevation south facing slopes to become active if temperatures rise this afternoon.


Primary Concern

The recent storm had peak intensity 2 days ago, and dropped more than 2 feet of snow in some areas including Turnagain Pass.  It was deep enough on Wednesday to make travel downhill quite difficult.  After yesterday's relatively clear weather that snow should be settled and consolidated to the point that travel is easier. 

A handful of large avalanches were caused by that storm, including a large natural that crossed the Portage road.  All the major avalanche programs in our region were doing explosive avalanche reduction work.  After the storm ended yesterday, explosive triggers were only causing small to medium avalanches occasionally, with nothing deeper than the recent storm snow.  The picture below shows one of the larger avalanches produced by Seward highway work yesterday. 

Colder temperatures and calmer weather will be acting to bring stability to the recent storm snow, but it still deserves a cautious approach today.


Secondary Concern

The larger avalanches that we've seen this week are suspected to be a result of deeper weak layers at the late January crusts.  The good news is it remains a less likely problem to encounter.  The bad news is it remains a tough problem to predict and avoid 100% of the time, even for the experts.

The buried crusts can be found in some areas at mid elevations between roughly 1900 and 3000 feet.  As those layers get deeper with each storm, the likely places to trigger deeper layers will be from shallow points that have been partially scoured by wind.

 


Mountain Weather

Storm totals yesterday morning reached near 2 feet of snow and up to 2 inches of water equivalent in some areas.  Areas such as Girdwood, Grandview, and Portage got more snow.  Summit lake got less, but still enough to cause concern. 

In the last 24 hours temperatures have cooled off a few degrees, wind has dropped, and precipitation ended by the afternoon. 

Today, a weak low pressure is spinning in Prince William Sound which may bring a few inches of snow.  Snowfall will end tonight and the weekend will bring a clearing trend.  Expect temperatures in the 30s and light wind. 


Fitz will issue the next advisory Saturday morning, March 2nd.

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.

Subscribe to the Turnagain Area Avalanche Advisory:

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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