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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Aleph Johnston-Bloom  
Sunday, February 7th 2016
Created: Feb 7th 4:13 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
TOTE Maritime
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! 

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

A MODERATE avalanche hazard exists throughout the advisory area. Human triggered avalanches are possible. Signs are pointing to a stabilizing snowpack but there is still the need for elevated caution as it adjusts to the load of the recent storm. Evaluate snow and terrain carefully and identify features of concern. Please use safe travel protocols, especially one rider on a slope at a time. Avoid travel on or under cornices and steer clear of glide cracks. 

***Elevated caution is also advised in the Summit Lake area. Please see yesterday's Summit Lake Summary for more information. 


Primary Concern

The recent storm deposited up to 3' of snow in the Alpine and had sustained winds in the 30-40s. There is evidence throughout the terrain of cross and top-loading. It is possible to trigger an wind slab in steep leeward terrain. Look for cracking, listen for hollow sounds and avoid stiff, pillowed snow. In addition, there is a lot of snow available for transport if the winds pick up at all today. There were a few small human triggered wind slab avalanches observed in the Tincan Common Bowl and along CFR ridge yesterday.

Winds and new snow have also added to already large cornices. These are quite hazardous, they often break much farther back than expected and can trigger avalanches on the slopes below. This happened throughout the region last weekend.

 

 Yesterday a snowmachine triggered a cornice fall and took an unexpected dip off the ridge into Warm-up Bowl (-1 Bowl).


Secondary Concern

We are continuing to investigate how the recent storm has bonded to the old snow surfaces, especially areas that may harbor persistent weak layers and rain crusts. Last weekend there was a large snowmachine triggered avalanche in Groundhog Creek, in the Johnson Pass region, that ran on buried surface hoar. We do not have recent information from that area and that layer may still be reactive. 

This last storm also may have buried a newer layer of surface hoar formed last weekend and/or faceted snow resting on the 1/27 rain crust. These layers were reactive during the storm but we did not observe human triggered avalanche activity on these layers yesterday or have concerning stability test results. Observers were reporting good bonding at the old snow/new snow interface and to the 1/27 rain crust. However, we are not ruling out the possibility of triggering an avalanche on a persistent weak layer today. Look and listen for whumpfing, collapsing and cracking, these are snowpack red flags that indicate unstable snow. Avoid thin spots, steep convexities and rocky areas. These are all possible trigger points in the terrain. This type of avalanche problem may be triggered by the 1st person on the slope or the 15th. It is important to not overload slopes with multiple riders all at once.


Additional Concern

Glide cracks still litter the terrain in the Treeline elevation:1000' - 2500'. New glide cracks continue to appear. Travel underneath should be avoided. They are totally unpredictable, regularly releasing and producing glide avalanches that would be unsurvivable. Yesterday a high mark was observed on Seattle Ridge directly underneath one. Scope out the terrain you want to travel in to avoid this type of exposure. 

 

 

Photo: glide crack on Petes South


Mountain Weather

Yesterday started out cloudy and there was a burst of precipitation in the morning. 2-4" of new snow fell in a few hours. There was afternoon clearing with partly cloudy skies and sunshine. Temperatures were in the 20Fs at upper elevations and in the 30Fs at the road level. NE winds were light throughout the day and overnight. 

Today will be partly sunny with increasing clouds in the afternoon and a chance of snow showers. Winds will be Easterly 10-25 mph and temperatures will be in the mid-20Fs to mid 30Fs.

Tonight and into tomorrow will be cloudy and snowy again as the next storm moves into the area. 3-7" of snow is forecasted to fall overnight. Rain and snow showers will continue to be the pattern for the next few days.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 27   4  .5 111 
Summit Lake (1400') 27   0  0  31
Alyeska Mid (1700') 30  .15   86

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 21   ENE  16  42
Seattle Ridge(2400') 24 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: Nov 18, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Closed
Placer River: Closed
Skookum Drainage: Closed
Turnagain Pass: ClosedOnly a few inches of snow sits at the motorized lot, not enough to open for snowmachining at this time. Updated Nov. 18, 2017
Twentymile: Closed
Seward District
Carter Lake: Closed
Lost Lake Trail: Closed
Primrose Trail: Closed
Resurrection Pass Trail: ClosedResurrection Pass trail is expected to open to snowmachine use during the 2017/18 winter season.
Snug Harbor: Closed
South Fork Snow River Corridor: Closed
Summit Lake: Closed

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.
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