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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Heather Thamm  
Thursday, January 22nd 2015
Created: Jan 21st 21:58 pm
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'
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The John Byrne Family
Special Announcement

Mark you calendars for January 23rd when the APU Outdoor Studies Department and Alaska Avalanche School present Winter Wildlands Alliance’s Backcountry Film Festival!! A night of entertainment, raffle prizes and a chance to rekindle our winter stoke is on tap. This is an AAS and F-CNFAIC fundraiser - a great way to support local avalanche education and information. Hope to see you there!

Do you ski or snowmachine in Hatcher Pass?  The Hatcher Pass Avalanche Center (HPAC) and the Alaska Avalanche School (AAS) are leading an Observer’s Workshop for backcountry enthusiasts who are interested in submitting snow and avalanche observations to the HPAC. More info can be found by clicking here.


The Bottom Line

Today the avalanche danger is MODERATE in the alpine. Human triggered wind slabs 4-10” are possible today and into the early evening above 2500’. 

The avalanche danger below 2500’ will remain LOW, but look out for rocks, ice, and dirt which will be extra difficult to see as new snow covers these early season hazards below 1500’.

*It’s also important to note several additional concerns- pay attention to ridgelines with large cornice features and avoid slopes with glide cracks (2000-3000’.) 


Primary Concern

Today we are expecting 2-4" of new snow above 1000’, with an addtional 3-6" arriving later today and into this evening. This morning ridgetop winds have picked up to 15-25mph from the East and are expected to remain moderate throughout the day. This could be just enough wind and new snow to form tender wind slabs (4-10”) in upper elevations above 2500'.

These wind slabs could be easily triggered on steep features (>35°) like convexities, along gullies, or just below a steep ridgeline. Pay attention to leeward slopes that are loading and make a note of how much snow is falling throughout the day.

Over the last few days’ cold temperatures have been weakening the surface snow by creating near surface facets. 2-6" of poorly bonded snow crystals are sitting on top of a firm bed surface (a dense wind slab at elevations above 3000’ and a melt/freeze crust at lower elevations.) This set up is less than ideal as we go into a storm cycle - depending on how the storm arrives this could be our next weak layer to track in the coming days. 


Secondary Concern

Many cornices have formed along ridgelines in the alpine throughout Turnagain Pass and Girdwood. These large unsupported snow formations are difficult to see sometimes or until you’re too close for comfort. Be aware of areas that have well formed cornices and give them extra space if you plan to travel along a ridgeline.  


Additional Concern

We have been continuing to monitor glide activity over the last week, with the most recent glide avalanche occurring several days ago on the South Face of Eddies. Glide cracks are unpredictable and it can be challenging to understand the exact nature of what triggers a glide to release. It is best to avoid traveling under or on slopes with large crevasse looking cracks. 


Mountain Weather

Yesterday skies were clear, winds were light, 5-10mph, shifting from the East to the West throughout the day.  Valley fog kept temperatures in the single digits (6-10F) at lower elevations with ridgetops reaching low 20’s F.

As of early this morning ridgetop winds have picked up to 15-25mph from the East and temperatures have also started to increase at upper elevations (low 20’sF.) No new precipitation was recorded in the last 24 hours.

Today 2-4” inches of snow is expected this afternoon with an additional 3-6” into the evening. Ridgetop winds are expected to remain moderate (15-20mph) throughout the day with temperatures steadily increasing to 30F.

More snow, up to 6” is forecasted for Friday. Temperatures should remain in the upper 20’sF to low 30’sF and ridgetop winds are expected to be light to moderate. 

*Seattle Ridge wind speed data was unavailable until 4am this morning. The below average/gust/dir are from 4am - 6am today. 

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 16  30 
Summit Lake (1400')
Alyeska Mid (1700') 15   0 19 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 20  Var  27 
Seattle Ridge(2400') 15  *ENE  *16  *34 

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, 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: Open
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
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