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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Heather Thamm  
Wednesday, February 3rd 2016
Created: Feb 3rd 5:21 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.
1 Low Below Treeline / Below 1,000' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
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The Bottom Line

Today the avalanche conditions will be increasing as a storm moves into our region. Right now a MODERATE danger rating still applies to the Alpine and Treeline elevations where wind slabs will be developing throughout the day. Should this storm intensify beyond the forecasted 6”, avalanche danger may reach CONSIDERABLE by late afternoon. Be on the lookout for changing conditions and alter your plans should you see any obvious signs of instability like human or natural avalanche activity.

The avalanche danger is LOW below Treeline where the snowpack is disappearing and an avalanche from above is unlikely.

*South of Turnagian Pass harbors a different snowpack structure where a variety of weak layers persist within the snowpack. Click HERE for an observation from Fresno Ridge yesterday and HERE for the Summit Lake Summary. We also found buried surface hoar responsible for a very large avalanche on Saturday in the Groundhog Creek drainage (Johnson Pass area).  If travelling in these areas a cautious mindset and careful snowpack evaluation are essential. 

 


Primary Concern

A series of storms with a Southerly flow will be moving through Southcentral Alaska over the next few days and into the weekend. Today ridgetop winds will be in the 20-30mph with 4-6” of new snow expected to fall throughout the day. Temperatures will continue to climb, which could bring rain as high as 1200’ by this afternoon.

Wind Slabs: Expect fresh wind slabs to be tender and isolated to leeward terrain features. These slabs will be growing throughout the day and could be as thick as 12” by this afternoon. Pay attention to the wind direction and where the snow is being loaded. Shooting cracks and any observed avalanche activity is a reminder that conditions are worsening and to avoid steeper slopes.

Cornices: Cornices will continue to grow with the addition of new snow and moderate winds. These features have been tender over the last few days and may release naturally with the additional weight of blowing snow. Give cornices lots of space by avoiding travel on or below them. 

 

Moderate Northeasterly ridgetop winds were observed in Summit Lake, Fresno Ridge yesterday as well as in Turnagain Pass.


Secondary Concern

Glides continue to be widespread throughout Turnagain Pass in the 1000’-2500’ elevation band. Since glide cracks can spontaneously release at any time, take the time to identify slopes with this unpredictable hazard. This week with warming temperatures and forecasted rain and snow, glides will continue widening and may release without warning. Avoid steep slopes that harbor a big “brown frown.”

 

 

 

Glide cracks observed on the East face of Seattle Ridge from Sunburst. Photo taken on Feb.1 by Graham Predeger. 


Mountain Weather

Yesterday Easterly winds started building in the afternoon; 20-30mph with gusts in the 40’s mph. Temperatures also started climbing with light rain falling below 700’. Overnight 3” of new snow was recorded at Center Ridge Weather Station.

Today moderate Easterly ridgetop winds will continue throughout the day. 4-6” of new snow is expected, and intensity will increase by early evening. Rain may push as high as 1200’.

Overnight 1.0” of water is forecasted which could bring another 12” of snow above 1200’ with rain below this elevation. Moderate Easterly winds may increase to strong by early tomorrow morning. Expect stormy conditions to continue for the next few days.



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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 31  0.3  92 
Summit Lake (1400') 31  trace  0.1  27 
Alyeska Mid (1700') 32  0.2  69 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 23 ENE  24  52 
Seattle Ridge(2400') 25  n/a  n/a   n/a  

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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