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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Heather Thamm  
Sunday, November 27th 2016
Created: Nov 27th 5:28 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
Alyeska Pipeline Service Company
Special Announcement

Motorized use on Turnagain Pass is closed due to insufficient snow cover.  Please see riding area status at the bottom of this page for the most up-to-date information.

Snowmachine Specific – Avalanche Awareness and Rescue at AMDS, November 30 @ 6:30 pm - 8:00 pm | FREE

Join CNFAIC forecasters at Alaska Mining and Diving Supply for a discussion on Avalanche Awareness and Rescue. Topics addressed will be: recognizing safe zones and avalanche terrain, situational awareness and obvious signs of instability, rescue gear and training, and the risks and challenges of riding in crowded areas.


The Bottom Line

The avalanche danger is MODERATE in both the alpine and at treeline on all aspects due to a widespread layer of buried surface hoar. Human triggered slab avalanches 1-2 feet thick are possible today and will have higher consiquences on larger slopes. Also triggering an isolated windslab up to 6" thick is possible on steep features near ridgetops. Be extra cautious choosing your route and don't hang out under glide cracks. 

***Observations from the Summit Lake area on the Kenai are showing a similar snowpack. Weekly summaries will begin on December 2nd.


Primary Concern

Over the last week the alarms have sounded due to a widespread layer of buried surface hoar sitting below 1-2 feet of snow. Observers continue to find this layer on all aspects and elevations throughout Turnagain Pass. Up until a few days ago human triggered and remote triggered avalanches were happening daily with a couple dozen avalanches reported over a 7-day period. These avalanches have been small to medium in size; just large enough to bury a person or seriously injure you in a ride. With time this layer has been adjusting to its load and becoming less reactive and harder to trigger.  Last nights snowfall, about 4 inches, arrived after winds calmed down and was just enough to cover up recent avalanche activity. Don’t forget buried surface hoar is a persistent weak layer and human triggered avalanche are still possible. This layer has not gone away and should be a major factor in slope choice today. Larger and/or steeper, more wind-loaded slopes that haven’t been ridden still have the potential to avalanche and could fracture once well onto the slope. Be aware of the consequences below you and keep an eye out for recent wind loading, shooting cracks and whumphing sounds.  Practice safe travel techniques like regrouping in safe zones and only expose one person at a time in avalanche terrain. This can be challanging to practice in crowded areas, thus be extra aware of other groups who may be traveling above or below you.

 

A view of avalanche activity on the popular Sunburst SW face. Photo taken Novemeber 24th before new snow from last night covered it up.  


Secondary Concern

Yesterday numerous shooting cracks were observed near Taylor Pass and Sunburst Weather Station, where moderate winds were activily loading Western aspects. Triggering a small wind slab up to 6” thick is possible in steep leeward terrain near ridgetops. Be aware of supportable and hollow sounding snow hidden below the four inches of new snow that fell overnight. Avoid steep slopes if you experience shooting cracks.

 

Several 10-20' shooting cracks were observed yesterday near Taylor Pass


Additional Concern

Several glide avalanches have released this week including one observed yesterday morning on the West face of Pyramid. Several glide cracks have been noted in popular terrain like Tincan’s Common bowl and the SW face of Sunburst. If you see glide cracks give these a wide berth, minimize time spent underneath, and remember these are totally unpredictable. They are not triggered by humans and are the entire snowpack releasing. 


Mountain Weather

Yesterday morning about an inch of new snow dusted Turnagain Pass and a trace was noted in Girdwood. Skies were overcast becoming obscured in the afternoon.  Easterly ridgetop winds were moderate (15-25mph) becoming light by the evening. Temperatures were on the rise all day, teens F to mid 20F’s. 

Overnight 4 inches of new snow fell in Turnagain Pass and only an inch in Girdwood. Temperatures remained just below freezing and winds were light from the Northeast. 

There is a chance for a few more inches of snow today. Ridgetop winds are expected to remain light and variable and temperatures should be in the mid 20F’s. 

Cooler temperatures and clear skies are expected tomorrow evening through Wednesday with another chance for snow near the end of the week.

***Sunburst Weather Station has not recording weather data since Nov.25th. We are currently assessing and hope to get it repaired soon.  

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 24  .4  20 
Summit Lake (1400') 23  trace  .1 
Alyeska Mid (1700') 26  .11 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812')  n/a*** n/a*** n/a*** n/a***
Seattle Ridge(2400') 21  SE/variable  26 

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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