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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Tuesday, January 10th 2017
Created: Jan 10th 5:52 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
Alyeska Resort
Special Announcement

UPCOMING EVENTS!!:

  • TONIGHT - Backcountry RESCUE discussion by team members of the U.S. Air Force 212th Rescue Squadron (RQS/PJ's) and Alaska Mountain Rescue Group (AMRG). Details HERE!
  • Thursday January 12th, 6:30pm, 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 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. Steep rocky slopes on Southerly aspects are also suspect for wet loose avalanches due to unseasonably warm temperatures at the upper elevations. Additionally, watch for glide cracks and avalanches, as these may be active this week.


Primary Concern

Blue skies, light winds and an uncharacteristically strong inversion continue to dominate our weather. Temperatures reached over 40F on some ridgetops yesterday, this is hard to believe from the single-digit cold air trapped in valley bottoms and parking lots. We got a report of a wet loose avalanche that ran in steep rocky terrain yesterday (photo below). With warm temperatures again today, these small wet loose slides, under rocks heated from the sun, are possible. If you decide to ride/ski on these steep South facing slopes, watch for surface warming in the top few inches of the snowpack and know that triggering a wet loose avalanche is possible.

Despite the 'green light' conditions, remember the snowpack has a poor structure on upper elevation slopes that have not avalanched and 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 warm temperatures and variability across the region, it's not impossible. Keeping up with safe travel protocol is key (exposing one person at a time, grouping up in safe zones and having an escape route planned).

Small wet loose avalanche on South facing Tincan Proper yesterday. Likely triggered by rocks warming loose snow in very steep rocky terrain directly facing the sun. Thanks to Nick Crews for passing this on to us! Read more HERE.

 


Additional Concern

Glide avalanches possible this week:  Continued warm temperatures at the upper elevations may enhance 'glide' in the snowpack. Watch for glide cracks to open up and a few may release. This pattern is similar to last week when 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) and Southerly slopes near Johnson Pass.


Mountain Weather

STATE OF THE SNOWPACK??:

Below is a quick look at the snowpack, in terms of how much there is today compared to other years on this day. For snow depth, we are sitting at the 2nd thinnest January 10th, yet there are only data since 2004 when the sensor was installed. For SWE (Snow Water Equivalent), we are sitting at just over half of what we would normally be for this time of year. It has been 12 days since the last snowfall and it's clear we are in need of a refresh!

 

 

 

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It was a sunny balmy day yesterday in the high elevations - temperatures at 4,000' were right around 40F. This is quite a contrast to the cold frosty single-digit-air trapped in the valleys. Ridgetop winds yesterday were light and variable and skies were clear.

Overnight, the upper elevation temperatures remained in the high 30'sF while valley bottoms, sitting in the cold pool, are anywhere between -5 and +15F. Temperatures should rise a few degrees during the day, similar to yesterday. Ridgetop winds are expected to be light, 5-10mph from the Northwest and skies clear.

As we keep looking into the weather model "crystal ball" for the next precipitation event, it looks like we could get some cloudy skies and flurries for the weekend. 

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 24  0 34 
Summit Lake (1400') 10  11 
Alyeska Mid (1700') 25  22 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 39!!  10 
Seattle Ridge(2400') 34  variable 

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: Dec 08, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Closed
Placer River: Closed
Skookum Drainage: Closed
Turnagain Pass: ClosedRain and snow have fallen in Turnagain Pass this week, but not enough to open for snowmachining. Continue to check back to this site for updates.
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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