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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Heather Thamm  
Thursday, February 18th 2016
Created: Feb 18th 5:48 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'
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Special Announcement

Saturday, February 20th Hatcher Pass Avalanche Center is having their annual fundraiser at Gov’t Peak Chalet near Hatcher Pass. This event will feature a slide show by local climber and ski mountaineer, Kirsten Kremer, a Silent Auction, Live Music and FUN!  Click HERE for more info.


The Bottom Line

Today a MODERATE avalanche danger exists in the Alpine (above 2500’) where cornices and lingering wind slabs may prove tender today with recent wind loading and increased sun exposure. At Treeline elevations (below 2500’) the danger is MODERATE where it is necessary to plan your route to avoid being underneath glide cracks and cornices.    

*Shallow snowpack zones: South of Turnagain Pass and the Summit Lake area have old weak layers in the snowpack where triggering a much larger avalanche is possible. This is something to keep in mind if you are headed to these zones. Click HERE for a recent photo of large Natural avalanche between Lynx Creek and Silvertip Creek. 


Primary Concern

Yesterday wind loading was observed in Turnagain Pass with Northeast ridgetop winds blowing 15-25 mph for most of the day. These fresh slabs could be tender and may awaken older deeper wind slabs (1-3’ thick) that formed over Valentine’s Day weekend. Be aware of this problem on slopes steeper than 35°, especially near rocks and on unsupported terrain features. Over the last few days observations have shown good bonding since Monday when two separate human triggered avalanches occurred in the Goldpan area of Turnagain Pass.  Avalanching has not been widespread, but this set-up needs to be considered, especially later in the day with increased sun exposure.

Loose snow avalanches: There is the potential for wet loose avalanches on steep southerly slopes and dry loose avalanches on steep northerly slopes. Remember these will release at your feet but may gain momentum and catch you from behind as you travel downhill. Evaluate terrain where taking a fall could have high consequences. 

Two small (D1) avalanches on 'Juniors'  West aspect of Seatte Ridge, apear to be skier triggered. No official report of timing of these avalanches, but likely occured on Monday.


Secondary Concern

Cornices have released naturally over the last few days and many have triggered fresh wind slabs. When approaching a ridgeline it can be challenging to recognize a safe distance. Be very skeptical of other tracks along ridgetops and don’t be tempted to walk to the edge for a better look. Cornices are notorious for breaking much further back than expected and if one releases it will be very large. Natural cornice fall activity should also be anticipated with warming from the sun, thus avoid spending time below cornices.

A massive cornice feature above 'Mamma's Bowl' on Seattle Ridge at the very top of the up-track.


Additional Concern

Glide Cracks cover many steep slopes between 1000’ to 2500’ and continue to release without warming. Over the last few days several have released and many have significantly widened. Be extra diligent about planning your route to avoid these unpredictable hazards. Minimize any time directly underneath and do not re-group below them.

A very large glide crack above a common "re-group" area in Main Bowl in Seattle Creek.

 


Mountain Weather

Yesterday was partly sunny becoming mostly cloudy by mid afternoon. Temperatures warmed to the mid 30's F along the highway, but remained cooler, low 20’s F at higher elevations. Moderate Northeast winds 15-25mph blew all day and just started subsiding this morning.  

Partly sunny skies are anticipated again today with Easterly ridgetop wind decreasing to 10-15mph. Day time temperatures with sun exposure may reach the mid 30’s F again today, but shaded area will likely remain in the 20’sF.

A similar pattern is expected tonight into tomorrow, but with increased cloud cover. 

 

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 28    102 
Summit Lake (1400') 24      30 
Alyeska Mid (1700') 27    86 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 19  ENE  12  35 
Seattle Ridge(2400') 22 

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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