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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Sunday, January 31st 2016
Created: Jan 31st 6:11 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.
1 Low Below Treeline / Below 1,000' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
 Show the Complete North American Avalanche Danger Scale
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The Bottom Line

Although a generally LOW avalanche danger exists in the Turnagain Pass region, there are a few exceptions that are keeping areas of 'yellow' in the picture. These are cornice falls, lingering wind slabs, glide avalanches and sluffs.

First, MODERATE danger exists along ridgelines where human triggered (or natural) cornice falls are possible and could trigger an old wind slab below. Second, a MODERATE danger exists at the mid-elevations where large glide cracks may release into destructive avalanches. And last, watch your sluff, these are expected to be fast moving with moderate to large volumes today.

*If you are thinking of going to the Summit Lake area, be aware that different avalanche problems exist within the snowpack. Click HERE to read yesterday morning's Summit Lake Summary. 


Primary Concern

After weeks of stormy weather, yesterday finally saw a true break in systems. Clear skies, calm winds and cool temperatures accompanied the many folks enjoying the excellent snow conditions around Turnagain Pass. With literally several hundred slope testers out there, the only avalanche activity seen and/or reported was several cornice falls and, believe it or not, one large 'natural' avalanche... (Many reports and photos were sent into us, check them out HERE!)

This avalanche was on the West face of Lipps ridge and released at 1pm yesterday. Skiers on the Cornbiscuit ridge reported seeing a powder cloud and snow in motion. At this point the trigger is unknown. There were skiers on the Lipps South face skin track; around the corner. There were no tracks leading into or out of the slide and no tracks near it on the ridge. We suspect this was a large wind slab triggered by a natural cornice fall. We have not seen any persistent weak layers that would lead us to believe this was remotely triggered by skiers on the South face. If anyone has further information on this slide please send us an observation or an email! 

Photo of the Lipps avalanche. Many more photos can be seen HERE.

 

Cornice falls and wind slabs today? 
With another clear sky day and light winds on tap, we are expecting very similar 'mostly' stable avalanche conditions. This means watching for lingering wind slabs in very steep rocky terrain and giving cornices a wide berth - see photo below. The sun is just starting to affect the snow and could help tip the balance for cornices on the verge of breaking. Keeping a look out for stiff hollow feeling snow and smooth wind pillows are good ways to suss out wind slabs on the steeper slopes.

**Although the snowpack is generally stable, the size and dangerous nature of the Lipps avalanche gives us pause to send out a green light today. Low danger incorporates small avalanches to be possible but not large ones. This 'outlier' avalanche is why keeping with good habits is ALWAYS important at times of good stability. These include:

- Exposing only one person at a time on a slope
Grouping up in safe zones
- Having an escape route planned if the slope slides
- Communicating plans with your partners

Photos below: Left photo (by Adrian Beebee), skier track on a chunk of cornice that was triggered on Tincan - close call!!  Right photo (Louis Sass), large natural cornice fall in upper Lyon creek.
  


Secondary Concern

We were expecting a glide release or two yesterday with the cooler temperatures and clearing skies but, no, we did not see any. It looks as though the glide cycle may be slowing down? Regardless, limiting/avoiding time under glide cracks remains prudent.


Sometimes it's hard to know if you are under a yawning glide crack if you can't see the whole slope.


Additional Concern

Sluff management! This will be one of those days that sluffs could be large, run quickly and catch you if you're not looking. 

Sluffs from yesterday:


Mountain Weather

Yesterday's nice day consisted of clear skies, light and variable winds and temperatures in the upper teens to low 20's F. 

Overnight temperatures have warmed at the upper elevations and cooled at the lower. An inversion is in place this morning with ~25F on the ridgetops and ~15F at 1,000'. Skies remain clear and should stay that way for today. We can expect temperatures to warm slightly through the day with the winds turning Easterly and picking up to the 10-15mph range by sunset. 

Monday, we are expecting a weak frontal band to move through from the East. A bump in Easterly winds, cloud cover and a chance for 1-2" of snow is expected.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 23   0 95 
Summit Lake (1400') 19   0  0 27 
Alyeska Mid (1700') 24   0 72 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 23  variable 10 
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

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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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