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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Saturday, April 2nd 2016
Created: Apr 2nd 6:05 am
1 Low Alpine / Above 2,500' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
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'
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Special Announcement

CNFAIC is going to Arctic Man for the fifth year in a row! We are excited be there all week and to offer two FREE companion rescue workshops. Click HERE for more information. We hope to see you there! Stop by the blue trailer and practice in the beacon park! Don't forget your beacon, shovel and probe!


The Bottom Line

Due to continued glide avalanche activity there remains a MODERATE avalanche danger at the mid-elevations. Destructive glide avalanches continue to occur sporadically in the forecast region. Glide avalanches are not triggered by people but release spontaneously. Otherwise, the snowpack is generally stable and human triggered avalanches are unlikely. If the surface crusts warm enough to melt today, wet loose slides will be possible on steep slopes. 

Summer use trails with avalanche terrain above should be avoided due to the threat of natural glide or wet avalanche activity from above. Byron trail in Portage Valley is not recommended and the Turnagain Arm Trail between Bird and Girdwood remains CLOSED for the winter.

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

 


Primary Concern

The primary concern for today will center around glide avalanches, for the countless time this season... These avalanches show no signs of abating and each day we see at least one new glide crack that has released. They are occurring on all aspects and predominantly at elevations ~3,000' and below. To make matters a bit more concerning, there have been a couple instances where a glide avalanche occurred where no crack was present the day before. This is a tough situation to manage considering the snowpack as a whole is mostly stable.

Continuing to avoid being under cracks is our best bet, and will be till the snow melts out and/or sluffs off the mountains for the summer.

Snowmachiners: The Seattle Ridge up-track is threatened by a large glide crack and a few smaller ones that have yet to release. 


Glide cracks and glide avalanches litter Seattle Ridge:


More of the same on Tincan Ridge:


Secondary Concern

As we work our way through this springtime regime and transition from a winter snowpack to a summer one, it's time to think about how the surface is warming/softening, or not warming/softening. This is not only for sussing out good ski/riding conditions but for wet avalanche hazards as well. Yesterday we saw unsupportable and wet snow below 2,500' where it was easy to initiate wet sluffs in steep terrain. Has this wet snow frozen overnight? Most likely there has been a shallow re-freeze limiting any wet avalanche hazard. However, temperatures climbing today and the possibility of sunshine may soften surface crusts again, allowing for wet avalanche activity to be possible.

Wet snow rule of thumb: If the snow is wet and mushy enough for your boot to sink in up to your ankle, or more, wet sluffs are possible and it's time to find a more supportable slope. Also, wet sluffs can be quite dangerous as the debris is heavy, can generate a lot of momentum and be extremely difficult to escape.

Wet and 'punchy' snow exists at the lower elevations:

 

*With the recent winds could we have wind slabs?  Possibly in the high elevations. These would likely be shallow and scattered along peaks above 3,500'. There is very little snow available for transport currently.

Winds blow a trace of snow around at the higher elevations where the snowpack is capped by a thin surface crust:


Additional Concern

We have yet to start seeing cornices begin to fall in earnest, yet it is still wise to give these very large snow features a wide berth along ridgelines and limit your time below them. Cornices typically calve off around now as we move into a springtime snowpack.


Mountain Weather

Weather conditions yesterday consisted of partly sunny skies, a cool Easterly breeze and warm temperatures out of the wind. Ridgetop winds during the past 24-hours have been blowing steady in the 15-30mph range with gusts over 50mph from a generally East direction. Ridgetop temperatures have been cooling slightly, from ~30F to the mid 20'sF.

For today we are expecting partly cloudy skies with a chance for a trace of snow above 1,500' and chance for rain below. It will be one of those inbetween storm days with sunny spots here and cloudy spots there. Ridgetop winds are expected to lessen to the 10-15mph range from the East and temperatures should climb a bit, to the upper 20's to 30F at the ridgetops.

Sunday is likely to be much the same as today. We will still be inbetween major storm systems with a chance for partly sunny to mostly sunny skies.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 37  rain  0.1  120 
Summit Lake (1400') 38   0 37 
Alyeska Mid (1700') 36  rain  0.1  106 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 27  NE  21  52 
Seattle Ridge(2400') 30  SE  23   47

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

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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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