Avalanche Advisory

Turnagain Area Avalanche Advisory
Thursday, December 14th 2017 5:30 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 CONSIDERABLE on all aspects and elevations above 1500'. Dangerous wet snow avalanches below 3,000' and large dry slab avalanches above 3,000' could release naturally today. The mountains have just undergone a two week onslaught of heavy snow and rain and the snowpack remains unstable. Natural large avalanches are possible and human triggered large slab avalanches are likely on slopes steeper than 30 degrees. Remote triggered avalanches from below slopes, next to and above are also possible. Cautious route-finding and conservative decision-making are essential. 

Below 1000’, where little snow exists, the avalanche danger is MODERATE where an avalanche releasing from above could send debris through steep channeled terrain into this zone. 

 Show the Complete North American Avalanche Danger Scale
3 Considerable Alpine / Above 2,500' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
3 Considerable Treeline / 1,000'-2,500' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
2 Moderate Below Treeline / Below 1,000' Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
Special Announcement

Scholarship Applications due on Dec 15th. The Friends of the CNFAIC have two scholarships dedicated to avalanche education for skiers, snowmachiners and all user groups. The funds generated to make these possible are in celebration of Rob Hammel and Amy Downing, their love and passion for the mountains, and to help others stay safe. 

Avalanche Problem 1

Wet Slab

Almost Certain
Very Likely


After two weeks of warm storms, heavy rainfall to 2,000-2,500' and an extended natural wet avalanche cycle, cooler air has finally arrived overnight. As of yesterday, the snowpack was still undergoing a wet avalanche cycle below 3,000'. One of the most notable avalanches was a large slab the released naturally just under the CFR ridge on Tincan, pictured below. Other smaller wet slab avalanches occurred yesterday in the Tincan area along with some on Seattle Ridge. Although natural avalanches are still possible, the natural cycle was decreasing yesterday and is on a continued downward trend today. This is due to cooler temperatures beginning to freeze the surface of the wet snow and only light precipitation expected today (1-2" snow). 

Recent wet/moist slab avalanche on Seattle Ridge


Today's avalanche problems: 
Wet slab avalanches below 3,000' and dry slab avalanches above 3,000' are our two main concerns, and they are big ones. We have very little information other than visual observations of the snowpack. What we know is very wet and saturated snow exists below 2,500'. Even though a surface crust may be forming with cooler temperatures last night, that will not rule out the possibility of a wet slab releasing today. These wet avalanches are extremely dangerous and even a small one can be unsurvivable. There are no tests that can be done for determining wet slab potential other than a stout refreezing of the pack stabilizing it.  


Avalanche Problem 2

Deep Persistent Slabs

Almost Certain
Very Likely


Above 3,000' moist to dry snow has fallen for two weeks now. Again, we have little information for these upper elevations at this time, but we do know prior to the storm cycle weak faceted snow with crust(s) sat near the ground. The slab on top of this weak foundation has now grown to several feet and much more in places. This presents a deep slab problem and will be guilty until proven innocent. In addition to this, storm slabs, wind slabs and cornices are all concerns in the recent storm snow. 

As you can see, for today, conservative route-finding will be essential considering the myriad of avalanche problems and the potential for large avalanches. 

Mountain Weather

Yesterday was a break in the heavy rain and skies were generally overcast. During the morning hours, .6" of rain fell in the Girdwood Valley and around .3" at Turnagain Pass before skies cleared. Ridgetop winds were moderate to strong from the East and have diminished overnight, although both the Sunburst and Seattle Ridge weather stations are not reporting we can look to the Max's mtn wind data to give us an idea. Temperatures that were very warm during the day (mid 40's at sea level and 30F at 2,500') have decreased overnight and are sitting near 32F at sea level and the upper 20's at 2,500'. 

For today, Thursday, light precipitation is on the way as a weak low pressure system spins to our East. Forecasted snow amounts are small - an inch for today and another inch for tonight. The good news is temperatures stay cool and the snow line should fall to 1,000' and possibly lower! Winds should be light to moderate from the North and West today before picking up tonight from the same direction tonight.

Looking ahead, a larger low pressure will bring another round of precipitation Friday afternoon through Saturday. This system looks to wrap in colder arctic air and snow should fall to 1,000', and possibly sea level. This system may favor East Prince William Sound and snow amounts in our area may be small. Stay tuned on tomorrow's forecast!

Glimpse of the Tincan meadows 


* Sunburst weather station is down due to loss of battery power.
** Seattle Ridge anemometer is rimed and not reporting.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 33  0.3  26 
Summit Lake (1400') 30  0.1 
Alyeska Mid (1700') 33  0.6  19 


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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') *n/a  *n/a   *n/a   *n/a  
Seattle Ridge(2400') 29  **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: 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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