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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Monday, January 18th 2016
Created: Jan 18th 6:12 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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Special Announcement

The Hatcher Pass Avalanche Center has updated the information regarding a snowboarder buried and killed in an avalanche Saturday. You can view their report HERE. Our condolences go out to the family and friends of the victim. We also would like to extend a heartfelt ‘Thank You’ to the many people who participated in the prompt rescue efforts.


The Bottom Line

There is a MODERATE avalanche danger today for both wind slab avalanches and glide avalanches. Lingering wind slabs (around 6-12" thick) will be possible for a person to trigger on steep slopes at the upper elevations. Additionally, an increase in wind this afternoon may begin forming fresh winds slabs in the Alpine. At the mid-elevations (1,000'-2,500') glide cracks continue to release. Limiting, or avoiding, any time under these cracks is recommended. 


Primary Concern

Saturday night brought a brief 'refresh' of snow to most areas in Turnagain Pass and Girdwood Valley. Around 3" of wet snow fell at 1,000' (which is now capped by a crust) and 6" of low density snow at the higher elevations above treeline. Moderate to strong Easterly winds along the ridgelines accompanied the snowfall. It was no surprise to see shallow wind slabs along the Tincan Ridge yesterday. Although these slabs were present, they were quite stubborn and hard to initiate on test slopes. The wind slabs sit on old snow (broken precipitation particles) with buried surface hoar intermixed, essentially Saturday's surface snow.

For today, Martin Luther King, Jr. Day, there are two types of wind slabs to watch for: Old and New. 

Old wind slabs: These older lingering wind slabs are in the 6" to a foot deep range. And, they can be tricky; meaning they may not release till you are well on the slope. They also may be obscured by a skiff of fresh snow. Quick hand pits and jumping on test slopes are good ways to suss these out.

New wind slabs: We are expecting an increase in East winds later in the day. Keep an eye out for active wind loading. Any fresh wind slab should be touchy and release easily (as opposed to the older, stubborn wind slab). These also can form on top of one another.

Photo below is Graham Predeger testing a fresh wind slab/cornice feature from the top of Seattle Ridge yesterday (credit: Sully). These small terrain features are good ways to test the snow without committing to steep avalanche terrain.


This photo below is from a test slope near Hippy Bowl on Tincan Ridge yesterday. What it shows are both a new wind slab (3-4" thick) stepping down to an older wind slab (6" thick). I know, it's tough to see, but hopefully you get the idea... 


Secondary Concern

After several days of glide cracks releasing on Turnagain Pass - some of which were 'front and center' on Seattle Ridge - there was only one new glide avalanche seen yesterday. This was a smaller glide on the South face of Wolverine Ridge around 1,500' in elevation.

Again, we preach avoidance for this avalanche problem. Avoiding, or doing your best to limit your exposure time, under these glide cracks is advised. There are still many large cracks looming - most notably on the East face of Seattle Ridge and on the South and West faces of Tincan ridge. These are the two areas most easily accessed by backcontry travelers.

Below is Heather's photo from Seattle Ridge on Saturday. You can clearly see the two glide avalanches from over the weekend as well as the looming brown crack on the next gully over to the right. With yesterday's 3-6" of new snow, many of these cracks are 'dusted over' and much harder to see now. 


Mountain Weather

Yesterday's weather consisted of mostly overcast skies, gusty Easterly ridgetop winds and warm temperatures (mid 30's at 1,000', upper 20's at 3,000'). Winds quieted down in the afternoon and have remained light from a generally East direction overnight. Warm air has been streaming in at the upper elevations overnight - Sunburst reported 32F at midnight, this station sits at 3,812'.

Today, we can expect mostly overcast skies again with a chance for sunny breaks in the clouds. Later in the afternoon and this evening, the Easterly winds should pick up along with light snowfall (rain below 1,000'). Ridgetop winds are forecast to be ~15mph from the East. Temperatures should cool to the mid-upper 20's F at the upper elevations and remain around 30F at 1,000'.

Overnight tonight and into tomorrow, an embedded low-pressure in Northern Gulf will bring a quick shot of snow above ~1,000'-1,500' with light rain below - accumulations look to be in the 3-6" range. Winds are expected to be 20-30mph from the East on the ridgelines and strong gap winds along Turnagain Arm.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 33  0.1  83 
Summit Lake (1400') 32 0.1  27 
Alyeska Mid (1700') 33  0.1  63 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 29  ENE  11  38 
Seattle Ridge(2400') 30  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: Dec 08, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Closed
Placer River: Closed
Skookum Drainage: Closed
Turnagain Pass: ClosedRain and snow have fallen in Turnagain Pass this week, but not enough to open for snowmachining. Continue to check back to this site for updates.
Twentymile: Closed
Seward District
Carter Lake: Closed
Lost Lake Trail: Closed
Primrose Trail: Closed
Resurrection Pass Trail: ClosedResurrection Pass trail is expected to 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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