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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Aleph Johnston-Bloom  
Wednesday, January 11th 2017
Created: Jan 11th 4:26 am
1 Low Alpine / Above 2,500' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
1 Low Treeline / 1,000'-2,500' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
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
The John Byrne Family
Special Announcement

Join us tomorrow night, Thursday January 12th, 6:30pm, for a FREE basic avalanche awareness and discussion by CNFAIC on the current snowpack in Turnagain Pass at the Alaska Avalanche School, Details HERE

* Hatcher Pass continues to have unstable conditions, check the Hatcher Pass advisory HERE if you are thinking of heading this way. Also - mark your calendars for the FREE rescue workshop at Hatcher Pass on January 14th. More info HERE

 


The Bottom Line

There is a generally LOW avalanche danger in the mountains surrounding Turnagain Pass. Although triggering a slab avalanche is unlikely, old hard wind slabs 1-3' thick sitting on faceted snow remain. With the right trigger spot and/or the right amount of force (several people and/or snowmachines) it may not be impossible to get a slab to pop out. Most suspect areas are unsupported slopes in steep rocky terrain.  Additionally, watch for glide cracks and glide avalanches, as these may be active this week.


Primary Concern

High pressure continues to dominate our weather pattern and not much is expected to change today with the exception of temperatures cooling throughout the day. The inversion is forecasted to break down as cold air pushes into the region.

It is always important to keep in mind that LOW avalanche hazard does not mean NO avalanche hazard. If heading out into the mountains today remember the snowpack has a poor structure on upper elevation slopes that have not avalanched and that were loaded by past winds (mainly North and East aspects). Hard wind slabs sit on faceted snow and/or buried surface hoar. Triggering a more dangerous slab that breaks in these layers is unlikely, however with the variability across the region, it's not impossible. Thin rocky areas and steep convexities with poor snowpack structure are most suspect. As always practicing safe travel protocol is key (exposing one person at a time, grouping up in safe zones and having an escape route planned). Looking at potential consequences of even a small slide in complex steep terrain is an important consideration. 

Buried surface hoar found in a pit on Repeat Offender yesterday. 1.10.17. This layer was not reactive but still intact. 


Additional Concern

Glide avalanches this week? Continued warm temperatures at the upper elevations over the past couple days may have enhanced 'glide' in the snowpack. Watch for glide cracks opening up and always avoid spending time underneath as they may release. Last week 3 glide cracks released. Known cracks exist on the South face of Eddie's, Goldpan (behind the Magnum ridge), East face of Seattle Ridge (Northern end), Main Bowl and Southerly slopes near Johnson Pass. Anecdotally we have been observing cracks releasing as temperatures cool after a warm up. Today might be one of those days. 

 

 

Glide cracks in Main Bowl. 1.10.17


Mountain Weather

Yesterday was clear, sunny and calm. The inversion was in place with ridge top temperatures above freezing and valley bottoms in the single digits. Overnight temperatures cooled slightly in the Alpine.

Today is forecasted to be similar with the exception of the inversion breaking down and cooling throughout the day into tomorrow as Arctic air moves in. 

Tomorrow will be colder and clouds are actually in the forecast tomorrow night in advance of a chance of snow Friday. Fingers crossed for actual accumulation. Timing and amounts of precipitation are still TBD. 

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 23   0  34
Summit Lake (1400') 10 0  0  11
Alyeska Mid (1700') 26 0  0  22

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812')  32  WSW 15 
Seattle Ridge(2400')  32  variable  8

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: Apr 28, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Closed
Placer River: Closed
Skookum Drainage: ClosedSKOOKUM DRAINAGE CLOSED TO MOTORIZED USE ON APRIL 1 annually as per the Chugach National Forest Plan document.
Turnagain Pass: OpenOpen thru May 14th.
Twentymile: Closed
Seward District
Carter Lake: OpenClosed May 1.
Lost Lake Trail: OpenClosed May 1.
Primrose Trail: OpenClosed May 1.
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: OpenClosed May 1.
South Fork Snow River Corridor: OpenClosed May 1.
Summit Lake: OpenClosed May 1.

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
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