Avalanche Advisory

Turnagain Area Avalanche Advisory
Wednesday, February 17th 2016 7:00 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 remains MODERATE today in the Alpine (above 2500’) where lingering wind slabs 1-3’ deep may prove reactive in steep terrain greater than 35 degrees. Skiers/snowmachiners, direct sun or cornice fall are all likely triggers, particularly later in the day when daytime temperatures peak. 

In the Treeline elevation band (1,000’ – 2500’) the danger is also MODERATE, where the potential for glide avalanches continues to be an issue.  

 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

Do you frequent Hatcher Pass? Mark your calendars!

TONIGHT! - FREE Avalanche Awareness Class hosted by Hatcher Pass Avalanche Center in partnership with F-CNFAIC and the Hatcher Pass Mountaineering Huts Group. Join CNFAIC Avalanche Specialist Aleph Johnston-Bloom at the Palmer High School Library from 6:30-8pm. 

Saturday, February 20th Hatcher Pass Avalanche Center is having their annual fundraiser at Gov’t Peak Chalet near Hatcher Pass. This event will feature a slide show by local climber and ski mountaineer, Kirsten Kremer, a Silent Auction, Live Music and FUN!  Click HERE for more info on both events.


Avalanche Problem 1

Lingering wind and storm slabs will still be possible to trigger in steep (>35 degree), wind-loaded terrain. Observations yesterday identified a weak interface in the snowpack at the boundary of the most recent storm and the snow surface it landed on, approximately 15-20" below the surface. Preserved precipitation particles remain sandwiched between stiffer snow layers above and below and were still reactive in stability tests. We suspect this structure combined with rapid warming and sunshine were reason the skier triggered wind slab avalanches in Goldpan area occurred on Monday and what the cornice triggered slab avalanches are running on as well. Avalanching has not been widespread and in general the snowpack has shown good bonding. However, this particular set-up needs to be considered, especially later in the day. In the Girdwood Valley, a thin rain crust was observed up to 3100' as the bed surface of wind/storm slabs that released during avalanche mitigation.

We have reached the time in Alaska where sun is a now a factor. 'It feels like spring' has been the general sentiment. Pay attention to increased solar input, warm ambient temperatures and changing surface conditions in the terrain you are traveling through. Warming may make slabs easier to trigger with the weight of a skier or snowmachine. Increased rollerball activity is a good indicator of the snowpack heating up rapidly and a sign that the surface is weakening. Avoid steep (>35 degrees), leeward slopes (South and West) late in the afternoon when the sun is at its strongest. 

Loose snow avalanches: There is the potential for wet loose avalanches on steep southerly slopes and dry loose avalanches on steep northerly slopes. Remember these will release at your feet but may gain momentum and catch you from behind as you travel downhill.  Avoid being knocked off your feet in steep high consequence terrain. 

Another look at at the skier triggered avalanches in Goldpan on 2/15.


Avalanche Problem 2

Yesterday we were able to get a closer look at the cornice fall on the South side of Magnum. It ran all the way to the drainage below and had pulled pockets of slab out with it. It covered the region where the skin track often goes. There were a number of reports from the advisory area of other large cornice falls that triggered the slopes below. Cornices will continue to be tender and travel on or below should be avoided. Remember they can break farther back than expected. Warming temperatures in the afternoon and direct sunshine may increase the hazard for both natural and human triggered cornice fall. 

Additional Concern

The glide avalanche problem continues. We observed two recent releases yesterday and glide cracks grow daily. All that needs to be said is avoid travel underneath glide cracks.



 Glide avalanche on Seattle Ridge.

Mountain Weather

Yesterday was mostly clear with periods of valley fog. Temperatures were in the low 20Fs to mid 30Fs. Winds were light and variable. Skies were mostly clear overnight. 

Today will be mostly sunny with a chance of valley fog. This afternoon may become partly cloudy. Temperatures will be in the mid 20Fs to mid 30Fs and winds will be Easterly 15-25 mph.

Tonight will be partly cloudy with another day of sunshine on tap for tomorrow as we sit under a ridge of high pressure for a couple days. 

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 24   0 103 
Summit Lake (1400') 22  0 0 30 
Alyeska Mid (1700') 25  0 0 85


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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812')  22 variable  19 
Seattle Ridge(2400')  28  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: 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.

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