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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Heather Thamm  
Sunday, March 13th 2016
Created: Mar 13th 5:54 am
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'
 Show the Complete North American Avalanche Danger Scale
Alyeska Resort
Special Announcement

Yesterday morning there were numerous car accidents on the North side of Turnagain Pass. No serious injuries were reported, but several vehicles were on their side. Please drive safe and be aware of black ice in the morning and evening.


The Bottom Line

The avalanche danger is MODERATE today above 1000’. Human triggered wind slabs and wet loose avalanches will be possible on solar aspects where radiation from the sun will be weakening the snow. On shaded aspects triggering a wind slab and dry loose snow will be possible on slopes steeper than 35°.  Glide cracks continue to release naturally and without warning and threaten a lot of mid elevation terrain. Avoid putting yourself in the runout of a glide crack.

*If you are headed to the Summit Lake area don't forget to check Summit Lake Summary.


Primary Concern

Yesterday several skier-triggered and snowmachine-triggered wind slabs were observed in the mid and upper elevation zones following a storm that dumped 12” of new snow in the alpine on Friday. Most of these slides were small, with the exception of a skier triggered wind slab on the North side of Cornbiscuit that was big enough to bury a person. Luckily the terrain allowed the debris to fan out at the bottom and the ski tracks didn’t look like the person was caught. If anyone has info about this avalanche or any others consider sending in an observation, by clicking HERE.

Triggering a wind slab will be possible on slopes steeper than 35° and could easily take you for a ride in undesirable terrain. On solar aspects pay attention to how the sun is warming the surface snow and avoid steep slopes when the surface becomes damp. Active roller balls or water dripping from cornices are obvious signs the snow is becoming unstable. On shaded slopes ease into terrain with caution and avoid terrain with high consequences (terrain traps, rocks, and usupported slopes) where taking a ride could have a poor outcome. 

A few other concerns to be aware of:

Loose snow: Don’t be surprised by loose snow sluffing on shaded aspects. Sluffing could be fast moving with the ability to entrain a significant amount of surface snow in big terrain. 

Cornice falls: Very large cornice features loom over many ridgeline and have a tendency to break further back than expected. Give them lots of space, and limit time under them. 

 

Skier triggered wind slab on the North side of Cornbiscuit as seen from the Sunburst parkinglot around 1:30pm yesterday. 

 

Snowmachine triggered windslab on West aspect of Seattle Ridge. Photo by Graham Predeger

 

Skier triggered wet loose avalanche just above the 'uptrack' on Seattle Ridge. 


Secondary Concern

There were several new glide avalanches seen yesterday in Turnagain Pass and Girdwood, including a very large glide release on the North side of Eddies and a smaller one on the South side of Sharks Fin. Glide cracks cover all aspects within the mid elevation band and remain a significant threat to popular terrain. This avalanche problem is impossible to predict and is not associated with human triggers. As long as glide cracks continue to open up, move and release, we will stress the importance of avoiding them. AVOIDANCE IS THE ONLY WAY TO MANAGE THIS AVALANCHE PROBLEM.

Recent glide release on the North side of Eddies. Click HERE for more pictures of recent glides.

 

 

Natural Wind slab on South Face of Lipps along side a growing glide crack. Photo by Liz Repetto 


Mountain Weather

Yesterday skies were sunny and temperatures reached a high of 44.5F at Center Ridge Weather Station by 12pm.’ Winds were light from the East switching to the West by the afternoon. No precipitation fell yesterday.

Overnight temperatures dropped into the mid 20’s F. Ridgetop winds became East with a sudden increase from Light to Moderate this morning.

Today Easterly ridgetop winds are expected to be light and skies will be mostly sunny. Daytime temperatures could easily reach the high 30’s F to low 40’s F by early afternoon. There may be some valley fog in Turnagain Arm.

Tomorrow looks like another repeat of today; partly cloudy, warm daytime temps, and freezing temperatures overnight. Winds are expected to remain light. 



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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 32  138 
Summit Lake (1400') 30  42 
Alyeska Mid (1700') 32  107 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 27  Variable  27 
Seattle Ridge(2400') 28  Variable  30 

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: Apr 28, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Closed
Placer River: Closed
Skookum Drainage: ClosedSKOOKUM DRAINAGE CLOSED TO MOTORIZED USE ON APRIL 1 annually as per the Chugach National Forest Plan document.
Turnagain Pass: OpenOpen thru May 14th.
Twentymile: Closed
Seward District
Carter Lake: OpenClosed May 1.
Lost Lake Trail: OpenClosed May 1.
Primrose Trail: OpenClosed May 1.
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: OpenClosed May 1.
South Fork Snow River Corridor: OpenClosed May 1.
Summit Lake: OpenClosed May 1.

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
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