Avalanche Advisory

Turnagain Area Avalanche Advisory
Wednesday, February 7th 2018 4:59 am by Aleph Johnston-Bloom
ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.
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The Bottom Line

The avalanche danger is MODERATE above 2,500' for triggering a slab 1-2' deep. Additionally, watch for cornices along ridgelines and sluffs in steep terrain.

*For the periphery zones, such as Girdwood to Portage Valley, and Johnson Pass to Summit Lake, more caution is advised where a slab could be larger and more connected.

Check out the Summit Lake Summary 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.
1 Low Treeline / 1,000'-2,500' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
1 Low Below Treeline / Below 1,000' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
Special Announcement

For all the Hatcher Pass users out there - Hatcher Pass Avalanche Center is having their annual fundraiser this Saturday night, Feb 10th at the Palmer Moose Lodge!! HPAC is a growing avalanche center for a high use zone with a high number of avalanche accidents in Alaska, they need your support! Click HERE for details.

Avalanche Problem 1

Persistent Slabs

Almost Certain
Very Likely


Very Large


Yesterday's storm brought a few inches of snow to Girdwood and Turnagain Pass. Portage Valley near the lake got 8-10". The winds died down in the early morning but the strong easterly winds from Monday night should not be forgotten today. We have been talking about the January 21st buried surface hoar layer for a couple weeks now. This layer has been responsible for the scattered avalanche activity over the past week and a half (including a large avalanche that occurred on Saturday on Twin Peaks). Slopes that got more wind effect/loading may now have a stiffer and more reactive slab over the buried surface hoar. Leeward slopes in the Alpine are the most suspect. The new snow may be may have covered up the surface signs of wind effect. It will be important to pay attention to where the snow feels stiff, looks pillowed or sounds hollow and watch for shooting cracks. Before committing to steep terrain, identify terrain traps like gullies, cliffs or rocks below and consider the consequences if even a small slab is released.  The new snow also fell on a fresh crop of surface hoar that developed last week. In Portage due to more new snow, even on lower elevation slopes, this February 5th surface hoar layer could be the layer of concern.  

*Deep Persistent Slab:  Weak snow can still be found near the ground at the upper most elevations in our forecast area, 3,000' - 5,000'. Although triggering a Deep Persistent Slab is very unlikely, it is worth keeping in mind that poor structure does exist at the high elevations. 

The January 21st buried surface hoar found in a snow pit yesterday under some stiffer wind-affected snow. Photo: Sam Galoob

 One of the lower piles of debris from the Twin Peaks avalanche that occurred on February 3rd.

The February 5th buried surface hoar layer under a couple of inches of new snow at Turnagain Pass. Photo: Sam Galoob


Additional Concern

Dry Loose

Loose Snow Avalanches, 'sluffs': In most places the snow is very loose and ’sluffs’ easily on the steeper slopes. The new snow will add volume to these.  Watch your ‘sluff’ and be aware of the consequences below you.

Cornices: Cornices are unpredictable and can break further back along a ridge than expected. Give these features plenty of space.

Mountain Weather

Yesterday was mostly cloudy and there were snow showers throughout the day. Temperatures were in the 30Fs at sea level and 20Fs at upper elevations. Winds were easterly and became light in the afternoon. Snow stopped in the evening and temperatures were in the low 20Fs. 

Cloud cover should diminish this morning and skies will become clear and sunny. There is the potential for some valley fog. Temperatures will be in the 20Fs and winds will be northerly 5-15 mph. Tonight temperatures drop into the teens and winds remain light and northerly.

Tomorrow and Friday should be clear and sunny with temperatures in the low 20Fs and light variable winds.  There is snow in the forecast for the weekend but the details are pretty uncertain. Stay tuned! 

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 28   2 0.1  64
Summit Lake (1400') 24  2  0.2   20
Alyeska Mid (1700') 25  2 0.09   52


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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812')  21  NE 26 
Seattle Ridge(2400') 22 ENE  12 

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: Mar 15, 2018 )

Glacier District
Johnson Pass: Open
Placer River: OpenPlease avoid private property and AKRR job site at Luebner Lake. Cross railroad tracks if needed, do not ride down tracks, it is illegal.
Skookum Drainage: OpenCross railroad tracks if needed, do not ride down tracks, it is illegal. FYI, Skookum drainage closes to Snowmachines on 4/1 as per the Chugach NF plan.
Turnagain Pass: Open
Twentymile: OpenCross railroad tracks at designated spot as you leave the parking area.
Seward District
Carter Lake: Open
Lost Lake Trail: Open
Primrose Trail: Open
Resurrection Pass Trail: OpenResurrection Pass trail is open to snowmachine use during the 2017/18 winter season.
Snug Harbor: Open
South Fork Snow River Corridor: Open
Summit Lake: Open

Subscribe to the Turnagain Area Avalanche Advisory:

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.

If you have comments or questions regarding CNFAIC operations or winter recreation management, please email
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