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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Heather Thamm  
Friday, January 2nd 2015
Created: Jan 2nd 4:36 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.
1 Low Treeline / 1,000'-2,500' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
0 NO RATING Below Treeline / Below 1,000'
 Show the Complete North American Avalanche Danger Scale
Alyeska Resort
Special Announcement

The CNFAIC Avalanche Rescue Workshop schedule for January 4th has been postponed due to lack of snow at the parkinglot level in Turnagain Pass. The workshop has been rescheduled for January 18th. Check our calendar for up to date info. 


The Bottom Line

Today the avalanche danger is MODERATE in the Alpine. Triggering a slab avalanche is possible in very steep terrain. Evaluate the snowpack carefully and consider the consequences before you choose to ski a steep slope.  

The Avalanche danger is LOW at treeline. Human triggered avalanches are unlikely, however it is possible an avalanche could be triggered from above and run into this elevation band. Use caution when crossing under sustained steep slopes and be aware of people above you.

There is No Rating below treeline due to not enough snow at this elevation. 


Primary Concern

It has been several days since a 3-day storm with high winds averaging 40mph subsided leaving behind stiff pockets of wind-loaded snow. There have been no recent reports of natural or human triggered avalanches, however the potential for triggering a wind slab in steep terrain still exists.

Wind slabs tend to be found in isolated pockets that can break above you. Avoid smooth pillow-like features on steep convexities, especially if high consequence terrain (rocks, trees, cliffs) is below you. Pay attention for shooting cracks or hollow sounding snow - these are obvious clues that a wind slab is unstable.

Evaluate the snow as you travel by probing with your ski pole to measure the stiffness and depth of the slab. Practice safe travel rituals like traveling one at a time in steep terrain and look for islands of safety to spot each other.  There are plenty of scoured ridges left behind from the 3-day wind event. Use these routes for safe travel into the alpine.


Secondary Concern

We have been actively tracking a buried surface hoar layer over the last two weeks. This layer is widespread throughout Turnagain Pass and has a 2-3’ slab sitting on top. The recent wind event has made the slab denser and more suportable. This is good news, as it will take more force to trigger this kind of avalanche. The bad news is the consequences are still high, and if you find the right spot it could propagate a large avalanche.

Avoid trigger points like shallow areas around rocks and convexities in steep terrain.  A cornice fall or wind slab avalanche could be enough weight to trigger a persistent slab. Give cornices a wide berth and pay attention to wind slabs in steep terrain as described in the primary concern.

An avalanche of this size could run into treeline. Keep in mind the runout zones and be aware of people traveling in steep terrain above you.

Buried surface hoar is still present and reactive in our test pits


Mountain Weather

Yesterday there was no new precipitation, skies were overcast and winds were moderate (10-25mph) from the Northwest. Overnight temperatures have started to drop into the low 20’s F.  

Northwest winds (10-25 mph) will decrease slightly this afternoon as temperatures cool into the teens tonight. Light snow flurries are possible today.

A high pressure system in the artic is building and is the culprit behind the cooling trend. Northwest winds are expected to decrease and light snow flurries may accompany mostly clear skies and cool temperature (10 to 25 F) into the weekend.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 28  34 
Summit Lake (1400') 29   6
Alyeska Mid (1700') 28 26 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 20  NW  26 
Seattle Ridge(2400') 22  14  44 

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 11, 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: OpenWide swaths of open river in the Placer Valley. Travel with extreme caution!
Skookum Drainage: ClosedSKOOKUM DRAINAGE CLOSED TO MOTORIZED USE ON APRIL 1 annually as per the Chugach National Forest Plan document.
Turnagain Pass: Open
Twentymile: ClosedClosed for the remainder of the 2017 season.
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

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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.


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.
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