Avalanche Advisory

Turnagain Area Avalanche Advisory
Wednesday, February 14th 2018 5:38 am by Wendy Wagner
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 1,000' on all aspects. Triggering a shallow wind slab avalanche will be possible on wind loaded slopes and cross loaded gullies. There is also the possibility for a person to trigger a larger slab that breaks in weak snow 1-2' deep. The danger is LOW below 1,000' where triggering an avalanche is unlikely.

 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.
1 Low Below Treeline / Below 1,000' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
Special Announcement

Coming up this Friday night, Feb 16th - The 2018 SNOWBALL!! Join the CNFAIC, our non-Profit Friends group and Alaska Avalanche School for live music by the Hope Social Club, silent auction, raffle, locally brewed beer and good people. This benefit supports avalanche safety in Southcentral Alaska, we look forward to seeing you there!!

Coming up Saturday, Feb 17th, from 11am-1230pm - Free Avalanche Beacon Practice with CNFAIC! We will be hosting a short workshop on how to effectively perform a companion rescue. Open to all users and all levels; swing by on your way to the hills if you are just getting into avalanche safety or simply need a refresher!

Avalanche Problem 1

Persistent Slabs

Almost Certain
Very Likely


Very Large


Yesterday's sunny skies revealed what most of us powder lovers do not wish to see after a snowfall event...wind. Monday night and Tuesday morning North and West winds wreaked havoc on much of the terrain around Turnagain, Summit Lake, Portage and the Girdwood Valley. Wind scalloped many snow surfaces, scoured some ridgelines to the rocks and sastrugi was reported on Tincan. Along with the winds, no natural avalanche activity was seen in the Turnagain area, but the Summit Lake region saw several shallow natural wind slab avalanches along with one that appeared to step down into an older weak layer.

For today, our main avalanche concern centers around a person triggering a large persistent slab avalanche up to 2' or more in depth. Below the storm snow and recent wind slabs (addressed below) sits the Jan 21 buried surface hoar we have been talking about for some time. This layer is roughly 1-2' below the surface and with recent wind and snowfall adding stress to it, the possibility for a person to tip that balance and initiate a larger slab avalanche is possible. There is also the possibility that a small wind slab or cornice fall could trigger this layer. We are back in a regime where no signs of instability are likely to be present before one of these avalanches releases and snowpit tests become unreliable. Therefore, assessing your terrain and the potential outcome if an avalanche breaking deeper in the pack does occur is key. Are there terrain traps below you? Cliffs? Are your partners watching and rescue ready? As we head into another period of high pressure (after today) keep these things in mind.

Northerly winds creating plumes off of Tincan Proper yesterday morning. (Photos: Jessie Haffener)

Anti-tracks on Tincan 


Avalanche Problem 2

Wind Slabs

Almost Certain
Very Likely


Very Large


Watch for wind slabs to be lurking intermixed with the variable surface conditions on the steeper slopes. These will likely be shallow, up to a foot thick, and stiff. They should be easy to identify with a rounded shape and hollow feeling. Watch for shooting cracks and places the wind crust becomes thicker. Cross loaded gullies could be a good place to find and trigger a wind slab as winds did blow at all elevations

Image below of a shallow wind slab on Tincan yesterday. Small terrain, small avalanche - Large terrain, small to large avalanche with higher consequences.

Additional Concern

Deep Persistent Slabs

Above 3,000' in the Alpine zones, several old weak layers of facets and buried surface hoar sit near the ground and in the mid-pack. This structure is most pronounced in areas with a thin overall snow cover, such as the South end of Turnagain Pass and the Summit Lake area. Recent wind slab avalanches Monday on Fresno ridge (Summit Lake zone) look as if they 'stepped' down into older weak layers in the snowpack. This is noteworthy and a reminder not to forget there are lurking old layers that could 'wake up' if one hits just the wrong spot.

Pictured below are shallow wind slab avalanches on Southeasterly facing Fresno ridge that looked to have triggered a deeper weak layer and subsequent larger avalanche lower on slope in the trees. (Photo: Jessie Haffener)


Mountain Weather

Sunny skies along with strong West the North ridgetop winds were over the region yesterday. Seattle Ridge weather station recorded averages at 50mph from the North with gusts to 68mph. Wind decreased significantly over the day and was light and variable overnight. No precipitation fell and temperatures were in the mid 20's along ridgetops and near 30F at 1,000'.

Today, Wednesday, a weak front is moving in with associated cloudy/overcast skies. There is a chance for a few snow flurries, but only a trace of accumulation is expected. Ridgetop winds are expected to pick up slightly from the Southeast and blow in the 10-15mph range. Temperatures will be near 30F at 1,000' and remain in the mid 20'sF along ridgetops. 

Sunny skies with generally light winds and cool temperatures are expected for Thursday and into the weekend. Northerly winds may pick up again on Saturday, stay tuned.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 28  66 
Summit Lake (1400') 22  25 
Alyeska Mid (1700') 29  58 


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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 22  NW  36 
Seattle Ridge(2400') 27   20 68 

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

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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.

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