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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Heather Thamm  
Saturday, March 19th 2016
Created: Mar 19th 6:20 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.
0 NO RATING Below Treeline / Below 1,000'
 Show the Complete North American Avalanche Danger Scale
The Woodland Family
Special Announcement

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Making plans for Arctic Man 2016? Don't forget your beacon, shovel and probe! CNFAIC will be there all week and offering two FREE companion rescue workshops. Click HERE for more info. We hope to see you there!


The Bottom Line

The avalanche danger is MODERATE in the mid elevation band between 1000’-3000’ where glide cracks continue to release naturally and without warning. Today the avalanche danger in the Alpine will increase from LOW to MODERATE by late morning as new snow and winds arrive in our region.  Chose your routes wisely to avoid glide cracks, and be on the lookout for freshly forming wind slabs, loose snow, and storm slabs as weather intensifies in the afternoon.

*If you are headed to the Summit Lake area don't forget to check Summit Lake Summary here.


Primary Concern

Today’s avalanche concerns will be based on how today’s changing weather affects our region. Should 4-8” of new snow and Moderate Easterly winds arrive as forecasted, expect surface instabilities (wind slabs, loose snow, and storm slabs) to increase in size throughout the day. Pay attention for rapid loading and blowing snow along ridgetops and how well this new snow is bonding with the surfaces below. If you see any obvious signs of instability like shooting cracks or recent avalanches be prepared to alter your plans. The following avalanche problems will be directly proportional to the amount of snow and wind we receive today.

Wind slabs – There is currently a lot of low-density snow available for transport on shaded (NE to NW) aspects. Expect wind slabs to grow in size by mid to late afternoon as winds starts to build from the East. Be on the lookout for blowing snow, shooting cracks and pillow shaped pockets on leeward aspects.

Loose snow: Dry loose avalanches will be possible in steeper terrain and will grow in size throughout the morning. If for some reason the sun makes an appearance today, slopes with a southerly tilt, may experience natural wet loose avalanches.  

Storm slabs: Storm slabs will likely be more of an issue later today in places protected from the wind. Again this will be directly proportional to the amount of snow that falls and will be an added reason to avoid steep terrain later in the day.


Secondary Concern

This week has been one of our most active glide avalanche cycles of the winter with dozens of dirty streaks observed in Girdwood, Turnagain Pass and Summit Lake. Yesterday a new glide avalanche was seen on the East side Seattle Ridge and another that occured late afternoon on a South aspect of Raggedtop in Girdwood. 

Glide cracks cover all aspects within the mid elevation band (between 1000-3000’) and remain a significant threat to popular terrain. As long as glide cracks continue to open up, move and release, we will stress the importance of avoiding them, which is THE ONLY WAY TO MANAGE THIS AVALANCHE PROBLEM. Remember these are totally unpredictable, release naturally and could be deadly if you were to get caught-up in one. It is the entire winter snowpack releasing at the ground. 

There is a lot of terrain where glide cracks can be challenging to see from the groud level. Here's an arial view taken of the SW face of Cornbiscuit on Wed, 3/16. Photo by Jared Gross. 

 

 

 

Penguin Ridge has been very active this week. This is a good reminder that there are summer trails that are threatened by avalanche terrain from above. This trail will remain closed through the winter. 

 

 

 


Mountain Weather

Yesterday skies were mostly cloudy and winds were calm. Daytime temperatures reached the mid 30’s F and overnight temperatures dipped into the low 20’s F. A trace of new snow fell overnight at Turnagain Pass.

Today a low-pressure system is moving into our region and 4-8” of new snow is expected today. Light Northerly winds will become East and will increase to Moderate by the afternoon. Temperatures will gradually warm throughout the day, with highs expected in the mid 30F’s. Rain is possible at lower elevations by later afternoon.

Snow showers are expected throughout the weekend and temperatures will steadily increase causing rain at lower elevations tonight into tomorrow. An additional 8-12” snow is forecasted for the upper elevations tonight through tomorrow morning. Winds are expected to remain Moderate from the East.  



PRECIPITATION 24-hour data (6am - 6am)

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 26  0.1  134 
Summit Lake (1400') 28  0.1  45 
Alyeska Mid (1700')  25 n/a  109 

 

RIDGETOP 24-hour data (6am - 6am)

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 22  NE 
Seattle Ridge(2400') 22  NE 

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: May 16, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Closed
Placer River: Closed
Skookum Drainage: Closed
Turnagain Pass: ClosedThanks all for a safe and fun season on the Chugach NF! Stay tuned for the 2017/18 season. #playsafe #snowtosealevel
Twentymile: Closed
Seward District
Carter Lake: Closed
Lost Lake Trail: Closed
Primrose Trail: Closed
Resurrection Pass Trail: ClosedResurrection Pass trail will be open to snowmachine use during the 2017/18 winter season.
Snug Harbor: Closed
South Fork Snow River Corridor: Closed
Summit Lake: Closed

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
© 2017 Chugach National Forest Avalanche Information Center. All rights reserved.
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