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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Kevin Wright  
Saturday, March 1st 2014
Created: Mar 1st 6:35 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.
 Show the Complete North American Avalanche Danger Scale
The Libby Group
Special Announcement

Due to warm temperatures, rain, and a decreasing snowpack all motorized areas in the Seward District and 20 mile are now closed.  The only areas open for snowmachine riding are Turnagain Pass, Johnson Pass north, Placer and Skookum.


The Bottom Line

Conditions are variable today.  An overnight freeze-up affected lower elevations, but not ridgetops.  Areas this morning with a hard surface crust will start with a LOW avalanche danger today.  As the daytime temperatures melt that crust away the danger may rise to MODERATE for wet loose avalanche conditions.  

Upper elevations will start at MODERATE this morning.  Temperatures at elevations over 3000 feet have been in the mid 30s all night.  Wet loose avalanches are also the major problem for this zone.  

 Overall the avalanche concern is minor.  Large avalanches are unlikely.  Small avalanches may be manageable depending on terrain.  The weather factors to keep in mind today are rising temperatures and sun exposure that may increase the problem as the afternoon progresses.


Primary Concern

We have seen quite a few small wet loose avalanches over the last few days.  They seem to be initiating in the top 5-6 inches of the snowpack where the water saturated snow is concentrated.  Check out this observation for a recent dye test of water percolation.

The worst case scenario with these avalanches would be stepping down into deeper layers and breaking out in a larger slab - a scenario we haven't seen with any consistency yet.

Wet avalanches will be more likely on sun exposed southern faces this afternoon.  While we expect most avalanches of this type to be small and slow moving, terrain considerations are still important.  Channeled terrain and terrain traps should be avoided.  Trees and cliffs could make even small avalanches dangerous.  


Secondary Concern

The lack of overnight freeze up high is actively destabilizing cornices.  These structures are always considered unstable, but as the snow temperature increases, their strength decreases.  Today is a good day to give cornices an extra wide berth and stay out from underneath them.


Additional Concern

The old persistent weak layer at the January crust interface is still present.  Any activity on this layer would be an outlier, but should be considered in steep terrain, especially at high elevations >4000'.  We simply don't have a lot of information on this problem since the most recent warmup began.  

This persistent weak layer has been responsible for many avalanches as recently as last weekend.  


Mountain Weather

The last precipitation - in the form of rain - passed through on Thursday.  This rain had a lot more effect on the Southern Kenai peninsula near Seward than Turnagain Arm.  

Partly sunny skies are expected today with patchy morning fog.  Temperatures this morning are in the 20s at sea level, but into the mid 30s at ridgetops.  It will get warmer through the day, especially in direct sun exposure.  Wind is light and variable.  

The weather pattern looks consistent through the weekend.  Cold at night, warm during the day.  The next chance of snow looks like Monday night and Tuesday.   

 

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: Nov 18, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Closed
Placer River: Closed
Skookum Drainage: Closed
Turnagain Pass: ClosedOnly a few inches of snow sits at the motorized lot, not enough to open for snowmachining at this time. Updated Nov. 18, 2017
Twentymile: Closed
Seward District
Carter Lake: Closed
Lost Lake Trail: Closed
Primrose Trail: Closed
Resurrection Pass Trail: ClosedResurrection Pass trail is expected to 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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