CNFAIC LogoCNFAIC Logo

Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Monday, February 1st 2016
Created: Feb 1st 6:08 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
Special Announcement

Girdwood Nordic Ski Club partnered up with the USFS and groomed a 2.8K cross-country ski loop near Center Ridge in Turnagain Pass on Friday. Groomed trails can be accessed just beyond the outhouses on the non-motorized parking area. For information on becoming a member and supporting the Girdwood Nordic Ski Club click HERE.


The Bottom Line

Although a generally LOW avalanche danger continues in most areas of the Turnagain Pass region, we have enough exceptions that combine for a MODERATE overall hazard at all elevations. These exceptions are: 1) Shallow fresh wind slabs may form today with a bump in winds at the higher elevations. 2) Cornices remain prime to fall and may trigger a slab avalanche below. 3) Glide avalanches are still releasing at the mid-elevations. 4) Large avalanches are possible in areas just South of Turnagain Pass where buried weak layers may exist.

*If you are thinking of going South of Turnagain Pass or to the Summit Lake area, be aware that different avalanche problems can exist and weak layers may be found within the snowpack. Click HERE to read Saturday morning's Summit Lake Summary. 


Primary Concern

It was a busy sunny weekend at Turnagain Pass to round out the final days of January. Tracks can be seen for miles along the ridgelines and slopes. We had some interesting avalanche activity but luckily no one was caught up in any of it. We had one very large snowmachiner triggered slide just South of Turnagain Pass on Saturday, more on this below. There were also several cornice falls (some of which triggered slabs below) and a glide avalanche.

In the heart of our forecast zone at Turnagain Pass, cornice falls seemed to be the main event. Check out this photo of a large cornice that is thought to have released sometime Saturday night. This cornice triggered a slab avalanche below taking out three sets of tracks from the day before. Read short report HERE. Photo credit: Susan Goodwin.

 

Avalanche concerns in the dry snow above 2,500' today:

WIND SLABS:
Winds along the ridgetops have picked up to the 15mph range overnight with stronger gusts from the East. These winds are forecast to remain, and possibly increase, throughout the day. This is just strong enough to transport snow and form shallow wind slabs. Watch for fresh wind drifted snow and active loading. Any fresh wind slab is suspect to be touchy and on slopes ~35 and steeper could avalanche.

CORNICE FALLS:
As seen in the photo above, these monsters are still falling (both naturally and human triggered) and have the chance for triggering an avalanche below. Limiting time under these, as well as giving them a wide berth above, is key terrain management.

SLUFFS:
With the clear skis and cool temperatures loosening the surface, sluffs on steep slopes can be expected.


Secondary Concern

Hundreds of glide cracks litter the mountains and a few of these continue to pop out and avalanche where people are recreating. One these was on Cornbiscuit over the weekend. Whether or not a crack will release is completely unpredictable and is why limiting time spent under these will be a message as long as the cracks continue to slowly open.

Glide avalanche on Cornbiscuit that released sometime in the past 36 hours. More on this HERE. Photo credit: Mike Loso.


Additional Concern

Yesterday a report came in of a large avalanche triggered off the Johnson Pass trail in the Groundhog Creek drainage on Saturday, January 30th. We were able to investigate the slide and it was indeed very large, 3' deep and 2500-3000' wide. See photo and video's below. The weak layer was buried surface hoar that sits roughtly 3' deep in the pack in this area. We have not seen this layer anywhere else in the forecast zone. It is most likely that the surface hoar was deposited in a short break in storms on 1/26 just prior to the 3+' of new snow that fell from 1/27-1/29. More details HERE.

We are suspect that other areas south of our core Turnagain Pass forecast area may harbor this or other weak layers.

Photo of the basin that avalanched (4,000', West aspect).


Video taken by party that triggered slide on Saturday January 30th.


Video taken the next day by forecasters.


Mountain Weather

Yesterday saw clear skies, light easterly winds and temperatures in the 20's F above treeline. Valleys stayed relatively cool and in the teens.

For today we could see some cloud cover stream as a weak frontal band stretches over us associated with a large trough in the Gulf. Winds picked up overnight from the East along the ridgetops to the 15mph range and may increase to the 20mph range today. Temperatures will be in the 20's F from the valley's to 3,500' with only a shallow inversion in place this morning. There is a slight chance for a flurry or two late in the day.

For Tuesday night through Wednesday another system moves in that should bring snow as low as 500'. Stay tuned.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 23  93 
Summit Lake (1400')  16  0 27 
Alyeska Mid (1700') 25  71 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812')  22  East 26 
Seattle Ridge(2400') 23  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: 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.
FCNFAIC