CNFAIC LogoCNFAIC Logo

Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Kevin Wright  
Monday, December 10th 2012
Created: Dec 10th 6:36 am
3 Considerable Alpine / Above 2,500' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
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.
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.
 Show the Complete North American Avalanche Danger Scale
The Bottom Line

Above treeline, a CONSIDERABLE avalanche danger will linger today.  The 10+ inches of snow combined with high wind over the weekend built very touchy wind slabs on top of the super weak snow from November.  We found the wind slabs to be very reactive to human trigger yesterday with remote and sympathetic avalanches in numerous places.  This trend is likely to diminish slightly today, but conservative terrain management  will still be important.


Primary Concern

The storm snow by itself didn't seem to be creating very reactive or connected avalanches yesterday.  Adding wind loading to the mix built the stiffness and tension required to build a slab.  Wind loaded areas steeper than 35 degrees should be approached with caution today.  Any areas with this combination in high consequence terrain should be avoided completely.  Check out the observations from yesterday for some more examples of skier triggered wind slabs.

Likelihood - human triggered likely

Trend - decreasing since yesterday

Distribution - Widespread above treeline

Size - small to medium

Watch a video of the avalanche in the picture HERE.


Secondary Concern

Below treeline where wind did not affect the new snow, the snowpack behaves differently.  We found very little difference in density between the fresh light powder and the underlying weak facets.  However, I wouldn't rule out the possibility of finding unstable storm snow below treeline.  If you find the right combination of an open steep slope at lower elevation, it may be able to avalanche as a slab or as a loose sluff.  This should be less dangerous than the wind slabs found up higher. 


Mountain Weather

The storm Saturday to Sunday morning dropped about 10 inches across Turnagain Pass.  Winds were strong from the east, reaching gusts over 70mph. 

Today looks like calm weather that won't contribute to avalanche problems.  A chance of snow is in the forecast with little accumulation.  Light wind and mild below freezing temperatures in the mountains.  The next chance of significant snow looks to be Wednesday. 


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). 

Wendy will issue the next advisory Tuesday morning, December 11th.

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 28, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: OpenPlease park on road in and leave the turnaround (near outhouse) open for trailers to turn around.
Placer River: OpenPlacer remains open but SKOOKUM DRAINAGE will close to motorized use on April 1st.
Skookum Drainage: OpenSKOOKUM DRAINAGE CLOSES TO MOTORIZED USE ON APRIL 1 annually as per the Chugach National Forest Plan document.
Turnagain Pass: Open
Twentymile: Open
Seward District
Carter Lake: Open
Lost Lake Trail: OpenPlease STAY ON existing and hardened trail surface through the lower sections of this route.
Primrose Trail: OpenPlease STAY ON existing and hardened trail surface through the lower sections of this route.
Resurrection Pass Trail: ClosedClosed for 2016/17 winter season. This is a non-motorized season. This alternates every other year and will open again during the 2017/18 winter.
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.


USFS SNOW AND AVALANCHE HOTLINE (907) 754-2369
If you have comments or questions regarding CNFAIC operations or winter recreation management, please email staff@chugachavalanche.org
© 2017 Chugach National Forest Avalanche Information Center. All rights reserved.
FCNFAIC