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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Aleph Johnston-Bloom  
Wednesday, February 10th 2016
Created: Feb 10th 4:23 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
Alaska Mountaineering and Hiking
Special Announcement

The Chugach National Forest Avalanche Information Center and Friends of the Chugach Avalanche Information Center are pleased to announce the launch of an observations program partnership with Hatcher Pass Avalanche Center.

By clicking the “Observations” link on both hatcherpassavalanche.org and www.cnfaic.org, users can now browse and submit Hatcher Pass observations. Data is mirrored on both sites giving Southcentral Alaska backcountry enthusiasts the ability to quickly browse recent snowpack and avalanche observations throughout the region. Please submit your own observations and spread the word to others.  Huge thanks to all those folks who have already submitted observations!

Save the dates! Hatcher Pass Avalanche Center and Friends of the CNFAIC are also joining forces to support FREE avalanche education at Hatcher Pass and in Palmer. There will be a FREE companion rescue workshop on Saturday, February 13th, 10:30am-12:30pm, Hatcher Pass Gold Mint Lot and a FREE avalanche awareness class Wednesday, February 17th, 6:30-8pm, Palmer High School Library. Click HERE for more info!


The Bottom Line

The avalanche danger is MODERATE today above treeline where it will be possible to trigger wind slabs 1-2’ thick on steep leeward slopes.  Avoid travel on or under cornices and steer clear of glide cracks. Watch for changing conditions as the next storm impacts the region.


Primary Concern

Cornices throughout the advisory area are very large and have the potential to be quite hazardous. A skier yesterday reported being caught off guard when one broke farther back than expected. Cornice fall can trigger avalanches on the slopes below or take you for a high consequence ride if you happen to go down with one in a bad spot. Give them a wide berth on ridgelines and limit time spent below. 

Wind slabs: It will be possible to trigger old wind slabs on steep leeward slopes today. As the storm moves in with additional snow and wind, this may create new tender wind slab and add weight to already wind-loaded areas.  Look for cracking, listen for hollow sounds and avoid stiff, pillowed snow. 

 

 

Skier triggered cornice fall in Warm-up Bowl (-1 Bowl) yesterday. Photo: Wendy Wagner


Secondary Concern

We’ve still have literally hundreds of glide cracks littering the mid-elevations in and around Turnagain Pass.  Many of these may not release at all, but we continue to see large and destructive glide cracks avalanching in or adjacent to popular ski terrain. Glide cracks are also widespread in high use snowmachine terrain and may release there just as easily! The bottom line is that they are completely unpredictable. It is best to minimize your exposure to this avalanche problem by avoiding time spent below glide cracks.  

 

 

Glide cracks in Main Bowl (1st Bowl). Photo: Wendy Wagner


Additional Concern

We are still not ready to say goodbye to the possibility of triggering a persistent slab in the periphery of our core advisory are. Observations Monday from the Lynx Creek drainage (South of Turnagain Pass) found a layer of buried surface hoar (BSH).  Likely deposited during the high-pressure weekend of Jan.30/31, it’s now buried by a 2-3’ slab.  This one data point Monday showed the BSH to be unreactive.  That is good news, but given the nature of persistent weak layers, we are not comfortable saying this is not going to be a problem. We just don't have enough information and this is a low probability, potentially high consequence set-up. There is still a chance of triggering an avalanche similar to the one in Groundhog Creek on January 30th, which luckily did not catch anyone. Ride slopes one at a time, park and regroup in safe areas and look for cracking and collapsing while traveling.


Mountain Weather

Yesterday started off partly cloudy and progressed to clear skies and lots of sunshine by the afternoon. Winds were light from the NE. Temperatures were in the mid-20Fs to mid-30Fs. There was a distinct warming period in the afternoon.

Today will be mostly cloudy with a chance of rain and snow showers increasing throughout the day. 1-2" of snow is forecasted. The rain/snowline is expected to be around 1100'. Temperatures will be in high 20Fs to mid 30Fs. Winds will be Easterly, 10-20 mph with the potential for higher gusts. 

Precipitation will increase overnight and the temperatures and rain/snowline will rise as the next warm, moist series of low pressure systems dictate the weather pattern.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 30   0 107 
Summit Lake (1400') 30  0  0  31
Alyeska Mid (1700') 30  0 0 92

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 25   NE  10  31
Seattle Ridge(2400') 27  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 25, 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

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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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