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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Heather Thamm  
Monday, March 14th 2016
Created: Mar 14th 6:23 am
1 Low Alpine / Above 2,500' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
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
Special Announcement

Yesterday a very large glide avalanche released on Penguin Ridge between Girdwood and Bird and pieces of debris reached the summer bike path. Luckily this trail is CLOSED for winter use and is marked with signs. However there are other trails free of snow that are not closed, but do have avalanche terrain above. With the return of warm sunny days and no snow near sea level it is best to avoid trails with avalanche terrain above.


The Bottom Line

The avalanche danger is MODERATE below 3000’ where glide cracks continue to release naturally and without warning. Above the glide cracks, in the Alpine, a generally LOW avalanche danger exists. This is an unusual and tricky set-up because there are many places where glide cracks threaten a lot of mid elevation terrain and moving around these features is not recommended. Chose your routes wisely, avoid the runout zone of glides, and be aware of crowded slopes by practicing safe travel rituals. 

For a good description of the North American Danger Scale check out this new video HERE.

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


Primary Concern

Several more glide avalanches were seen yesterday between Girdwood and Turnagain Pass. The most notable was on Penguin Ridge. This is the third large glide to release on Penguin this week, however yesterday’s was the largest and pieces of debris reached the bike path below.

Glide cracks cover all aspects within the mid elevation band (between 1000-3000’) and remain a significant threat to popular terrain. This avalanche problem is impossible to predict and 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, which is THE ONLY WAY TO MANAGE THIS AVALANCHE PROBLEM.

Penguin Ridge Glide avalanches: Lookers left first reported on Sunday morning, 3/13. Middle glide avalanche is from 3/11, and the one on the right is from 3/9.

 

 

View of Penquin Ridge from accross Turnagain Arm. Note the large glide crack still opening up near the furthest right glide avalanche.

 

 


Secondary Concern

Over the weekend slope testers (motorized and human powered) pushed into steep terrain with several small human triggered avalanches occurring Saturday. Yesterday Turnagain Pass was very crowded and no new activity was reported. As we move further away from Friday’s 12” storm this is a good indication that generally stable avalanche conditions exist in the alpine.

With sunny weather and spring break crowds it is extra important to be aware of other people in the area. Should you choose to enter into steeper terrain only expose one person at a time and regroup in safe zones.  LOW DANGER DOES NOT MEAN NO DANGER, triggering one of the following avalanche problems is still possible today.

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. On solar aspects pay attention to how the sun is warming the surface and be aware of wet loose avalanches should the snow become wet and saturated.

Cornice fall: 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. 

Windslabs – On shaded aspects in very steep terrain it is still possible to find an old isolated wind slab. This will be more likely in extreme terrain with rocks, cliffs and unsupported features.

 


Mountain Weather

Yesterday skies were mostly sunny and temperatures reached the mid 40’s F.  Winds were light from the East, switching to a Westerly directly last night. Overnight temperature dropped back into the low 20’s F and no new precipitation has been recorded since Friday (3/11).

Today skies are expected to be partly sunny with light NW winds. Daytime temperatures could easily reach the high 30’s F to low 40’s F by early afternoon. This evening cloud cover may increase with a slight chance of snow showers.

Tomorrow light snow showers will move through the region, but not much accumulation is expected. Temperatures are expected to remain mild. 

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 33  137 
Summit Lake (1400') 26   0  42
Alyeska Mid (1700') 32  109 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 27  Variable  18 
Seattle Ridge(2400') 28  SE  29 

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: May 16, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Closed
Placer River: Closed
Skookum Drainage: Closed
Turnagain Pass: ClosedThanks all for a safe and fun season on the Chugach NF! Stay tuned for the 2017/18 season. #playsafe #snowtosealevel
Twentymile: Closed
Seward District
Carter Lake: Closed
Lost Lake Trail: Closed
Primrose Trail: Closed
Resurrection Pass Trail: ClosedResurrection Pass trail will be 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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