Avalanche Advisory

Turnagain Area Avalanche Advisory
Saturday, December 3rd 2016 7:00 am by Heather Thamm
ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.
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The Bottom Line

A MODERATE avalanche danger exists in the mountains surrounding Turnagain Pass at all elevations above 2,000' and on all aspects. Wind slab avalanches around a foot thick will be possible to trigger on slopes loaded by blowing snow. Larger slab avalanches are also possible in areas less traveled where a weak layer remains in the snowpack 2-3' deep. Safe travel protocol will be essential this weekend.

Caution is also advised in periphery areas like Portage Valley where windslabs are possible on ice climbing routes. 

*** Summit Lake weekly summary can be found HERE.

 Show the Complete North American Avalanche Danger Scale
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'
Special Announcement

Tonight is the 8th Annual Alyeska Ski Patrol Auction, a fundraiser to benifit the Alyeska patrol avalanche canines. The event will be in Girdwood at the Sitzmark, 8-10pm. For more details click HERE.

Avalanche Problem 1

Don’t forget your down jacket, mittens, and thermos today. Moderate Northwest winds (15-30mph) and single digits (F) temperatures could easily bring the windchill factor near -20F, especially in the upper elevations. These same winds could also be adding stress to an early season snowpack.  Watch out for isolated windslabs near ridges or a wind slab that could be sitting on the Nov 16 layer of buried surface hoar. If this is the case, a 'typical' wind slab avalanche could step down and trigger a much larger slide releasing 2-3' deep. Keep in mind, these could pop out mid-slope. Be aware of your exposure and avoid pillow shaped snow on steep unsupported terrain features. Snow that feels supportable, hollow or drumlike is suspect and cracking will be an obvious sign that this snow is unstable.   

Be prepared for cold weather, travel one at time between safe zone, and adjust your plans if an area becomes too crowded.

A normal weekday on the popular ski track up Sunbursts SW shoulder. Photo taken yesterday, Dec.2 at 12:30pm.

Avalanche Problem 2

A layer of buried surface hoar, 1-3' deep, still remains on many slopes throughout Turnagain Pass and in the Summit Lake area. During the past two weeks, many popular slopes have avalanched (removing the weak layer), and been covered again by recent snow. This makes it really hard to know the full extent of which slopes still have this weak layer set-up, especially in places that haven’t seen much traffic.   

Keep these questions in mind today before committing to a route or descending: 

  • “What are the consequences if this slope avalanches?” 
  • “Are there other groups above me or below me?”
  • “What is my plan if this slope avalanches?”

Additional Concern

It's been roughly a week since we have seen or heard of a glide crack releasing - but the cracks continue to widen despite the cold weather. Once again, limiting your exposure under these is highly recommended. 

Mountain Weather

Yesterday was mostly cloudy with temperatures in the low to mid 20F’s. A generally NW wind direction was recorded at ridge tops. Sunburst weather station recorded light NW winds while Seattle Ridge weather station experienced sustained moderate winds (15-25mph.)

Overnight temperatures have been falling into the single digits in the upper elevations and low teens (F) along the road corridor.  No new precipitation was recorded in the last 24 hours. 

Today looks similar. Temperatures should remain in the single digits with a high of around 10F at lower elevations. Northwest Ridgetop winds are expected to remain moderate (15-25mph) with a chance of isolated snow showers in the afternoon. 

Northwest flow are expected to bring cold arctic air and moderate ridgetop winds to Southcentral, Alaska throughout the weekend. Anticipate clear skies tomorrow.


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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 14  23 
Summit Lake (1400') 17 
Alyeska Mid (1700') 15  12 


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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') NW  15 
Seattle Ridge(2400') 10   NW 11   35

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: Oct 05, 2019 )

Glacier District
Johnson Pass: ClosedClosed
Placer River: ClosedClosed
Skookum Drainage: ClosedClosed
Turnagain Pass: ClosedClosed
Twentymile: ClosedClosed
Seward District
Carter Lake: ClosedClosed
Lost Lake Trail: ClosedClosed
Primrose Trail: ClosedClosed
Resurrection Pass Trail: ClosedClosed. Will be open for the 2019/20 season pending adequate snow cover.
Snug Harbor: ClosedClosed
South Fork Snow River Corridor: ClosedClosed
Summit Lake: ClosedClosed

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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.

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