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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Saturday, February 27th 2016
Created: Feb 27th 6:37 am
3 Considerable Alpine / Above 2,500' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
3 Considerable Treeline / 1,000'-2,500' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
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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Special Announcement

A special thanks to everyone who attended the 2nd annual Snowball last night at the Taproot!! This was a joint fundraiser between the Alaska Avalanche School and the Friends-CNFAIC and all proceeds directly support avalanche information and education in Alaska! 

CLOSE CALL IN THE SOUTH FORK OF EAGLE RIVER Thursday, Feb 25th:
We received a report about a large avalanche triggered in the Harp Mountain area (Eagle River, South Fork) on Thursday, February 25th. This slide caught and carried a skier and buried and killed a dog. Please read the account from one of the members of the party HERE. We are very thankful the people involved are ok and are thankful they are willing to share their story. 


The Bottom Line

A CONSIDERABLE avalanche danger remains at all elevations above 1,000'. This means human triggered avalanches are likely on slopes 30 degrees and steeper and natural avalanches are still possible. Cornices are huge and could fall, glide cracks are still releasing and storm snow/wet snow avalanches remain concerns. Elevated caution is recommended. Very cautious route finding and conservative decision-making are important if venturing into the mountains today. 

The danger is MODERATE below 1,000' where debris from an avalanche above may run into channeled terrain.

Dangerous avalanche conditions also exist in the Summit Lake area. See this morning's Summit Lake Summary and click HERE for recent observations from the last few days.


Primary Concern

Today will be the 6th day of stormy weather along Turnagain Pass and the surrounding region. We have seen the rain/snow line fluctuating between 500' and 2,000' and a total precipitation (water) for this six day period of 10" at the Center Ridge SNOTEL station!! That equates to over 10' of snow in less than six days at the upper elevations. That said, our snowpack is well above average at 2,000' - it's just a bit damp. For today, we are expecting a slight break in precipitation before another wave moves in tonight. Around 3-5" of snow is forecast above 1,800' today with rain below and 5-10" of snow tonight above 1,400', again with rain below.

As the stormy weather continues, so do our avalanche problems. Although most of the avalanche activity we have seen occurred the first day of the storm cycle (Sunday 2/21), we are still seeing a few large slides pull out here and there. The most notable was a glide avalanche on Seattle Ridge yesterday morning. Things to keep in mind if you are headed out today:

Cornices: Natural cornice fall activity is possible and could trigger an avalanche on the slope below. This is something you want to avoid traveling on or underneath. Cornices will be tender and could break farther back than expected. As Aleph said yesterday, falling down the slope with a refrigerator to school bus sized chunk of snow on your snowmachine or skis would be terrible, if not deadly.

Storm Slabs: Fluctuating temperatures and snowfall may combine to create storm slabs as new layers of snow are deposited. Pay attention to how well the new snow bonds to the snow below. 

Wind Slabs: Winds today will continue to add stress to very large wind slabs in leeward terrain. Triggering one of these could be very dangerous due to the depth of slab. Avoid steep wind-loaded slopes. 

Glide and Wet Avalanches: See below.


Secondary Concern

Glide avalanches still remain a real concern in the area. The many cracks that littler the mid-elevations are hard to see now with the snow filling them in, but there is no mistaking this brown streak on Seattle Ridge. This slide released early yesterday morning and was caught on the RWIS Turnagain Pass camera. Another reason to give avalanche terrain a break for this storm cycle.

Photo: Glide avalanche on Seattle Ridge - uncomfortably close to the motorized up-track...

 

Photos below are of the RWIS camera before and after the glide release

  


Additional Concern

Rain on the snowpack up to 1,800' today will keep wet avalanche concerns in the forecast. Natural wet loose and wet slab avalanches will be possible in the mid elevation bands and human triggered avalanches are likely in steep terrain. Watch for areas with wet, saturated and unsupportable snow, that is an indication that the snow is losing strength and avoid terrain traps. Wet snow can be very hazardous especially if it gets moving and stuffs you into a bad spot.


Mountain Weather

Skies were patchy yesterday with showery precipitation along Turnagain Arm. Snow fell above 1,500' with rain below. We picked up roughly 1-1.5" of water through the region with a foot or so of heavy wet snow above treeline. Winds have remained strong out of a generally East direction, in the 20-40mph range along the ridgetops. Temperatures were warm, up to 40F at 1,000'...

For today, we have .3-.5" of rain on tap below 1,500' and 3-5" of snow above 1,800' (snow/rain mix between these elevations). Skies should be mostly cloudy and temperatures warming up through the day after dropping to 32F at 1,000' overnight. Ridgetop winds are slated to remain strong, 30-40mph averages with higher gusts from the East. Tonight precipitation should increase with 1-1.5" of water forecast and a rain/snow line dropping slightly to 1,400'. 

This wet and stormy pattern looks to remain through tomorrow with a 'possible' break on Monday.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 33  1.4  136 
Summit Lake (1400') 34  0.1  42 
Alyeska Mid (1700') 33  1.1  105 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 26  NE  29  81 
Seattle Ridge(2400') 27   -

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
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