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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Kevin Wright  
Saturday, February 8th 2014
Created: Feb 8th 6:50 am
3 Considerable Alpine / Above 2,500' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
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

If you haven't been watching the weather closely you may have missed the storm that happened on the Kenai yesterday.  Snowfall was somewhat localized with both Seward and Girdwood only getting a little snow.  Turnagain Pass came out as a big winner from this one.  By 2pm yesterday there was a confirmed 10 inches at the road.  Center Ridge snotel site is now reading a 16 inch increase in snow depth from yesterday.  

The snow came in cold and dry with some wind.  Windslab is the primary reason that pockets of CONSIDERABLE may be found at any elevation where wind was transporting the new snow.  We can expect soft wind slab sliding easily on the old firm crust surface.  Avalanches occurring from the new snow should be low volume and have relatively little force.  

Anywhere the wind slab is not present, sluffs may be initiated on steep terrain in the new storm snow.  Underneath the new snow we still have the old deep slab concerns that have kept us at a MODERATE danger rating recently.


Primary Concern

Fresh wind slab from yesterday's storm is the most likely problem to find today.  This should be a manageable avalanche concern - not dangerous unless you jump into high consequence terrain without sluffing out the run first.  I expect a lot of slopes will be easily triggered by skiers today, but this is light density snow and should behave in a predictable manner.  It's the perfect scenario for controlled ski cutting (in areas of safe terrain exposure).  The CONSIDERABLE danger rating is for likely human triggered avalanches - of small size, in many areas.

The good skiing will probably be sheltered areas where wind didn't have a lot of effect.


Secondary Concern

We've been tracking multiple buried weak layers for quite some time.  The big meltdown in January caused many large deep slab avalanches, but since cooler temperatures took over, the mountains have gone dormant.  We still have some concerns about the persistent weak layers (persistent means they stick around for a long time).  The areas of greatest concern include elevations above 3500 feet where the rain and warm temperatures had less effect on the snowpack.  It may still be possible for a person to initiate a collapse and trigger a deep avalanche.  

This is a MODERATE type concern of low likelihood but higher consequence.  


Mountain Weather

The big news in the weather history is the storm that blew through yesterday.  Areas hardest hit by this storm appear to be glacier regions of the southeast Kenai peninsula, Prince William Sound, Turnagain Pass (16 inches?) and Grandview (10-12 inches).  If instrumentation is reading correctly, snow density is somewhere around 5%, or very light dry powder.  Wind at the ridgetops was blowing 40s-60s mph on Sunburst from an ENE direction.  Temperatures during the storm started cold, in the teens and low 20s and rose to what they are currently (mid to high 20s).

Today - mostly cloudy skies, temperatures in the 20s, and a light NW wind.  

Weather trend looks to be colder and windier from the north going into next week.  No major storms are on the horizon for the coming week.

 

 

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.


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