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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Sunday, February 14th 2016
Created: Feb 14th 6:00 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

We had a GREAT turnout at the 2nd annual Hatcher Pass Avalanche Rescue Workshop!! Over 70 people attended this community supported clinic. A big thanks to the Hatcher Pass Snow Riders Club for hosting a BBQ afterward. This workshop was put on by Hatcher Pass Avalanche Center in partnership with the Friends of the CNFAIC. 

Don't forget about the FREE avalanche awareness class in Palmer Wednesday, February 17th. Everyone is welcome, no registration. It is from 6:30-8pm at the Palmer High School Library. Click HERE for more information!

 

 


The Bottom Line

There is a MODERATE avalanche danger in the mountains surrounding Turnagain Pass for a variety of avalanche problems. First, glide avalanches, that release on their own, are possible at the Treeline elevation band (1,000-2,500). Second, human triggered wet loose avalanches will be possible at this same Treeline band. Third, Wind slab avalanches, up to 2' thick, and cornice falls are possible in the Alpine (above 2,500') where it has been lightly snowing and blowing.


Primary Concern

Although there are many human triggered avalanche concerns out there, glide avalanches remain the primary concern due to their destructive nature. This season is turning out to be a season where mapping glide cracks and limiting/avoiding time under them is just part of the game. The most recent glide we know of that has released at Turnagain Pass was 3-4 days ago on the Eddies ridge

Photo: Glide avalanche on Eddies, released sometime late 2/10-early 2/11.


Secondary Concern

While many folks are waiting for the skies to clear and temperatures to cool off before venturing into the mountains, it has been snowing a bit and blowing quite a bit over the past several days in the Alpine - above 2,500'. Specifically, between 1 and 2 feet of new snow has fallen over the past 3 days with winds in the 20-25mph range on the ridgetops from the East. Due to lack of travel and visibility in these areas we don't have first hand data as to how the wind driven snow is bonding, if cornices are falling and the like. However, we know from past experience that this warm snow is quite sticky and stabilizes relatively quickly. This will most likely be the case for today and into the week. Nonetheless, things to watch for at the upper elevations:

Wind Slabs:  Steep slopes that have been, or are currently being, loaded with wind deposited snow are suspect for triggered a wind slab avalanche. These could be 1-2' or more thick. Watching for cracking in the new snow and jumping on small terrain features and test slopes can be good ways to see how well slabs are bonding. 

Cornice Falls: GIVE CORNICES a wide berth!! these are likely to be tender with the warm temperatures and could be deadly if you were to take a fall off a ridgeline with one. Also, similar to glide avalanches, limit time spend under cornices.

*Shallow snowpack zones: South of Turnagain Pass and the Summit Lake area. These areas have old weak layers in the snowpack that, if loaded with enough snow/wind, could produce a large avalanche. This is something to keep in mind if you are headed to these zones this week with the expected clear skies.


Additional Concern

It will be another moist day out there. Temperatures dipped to 32F at 1,000' overnight and it is lightly snowing at the Pass this morning, but temperatures are forecast to climb up again today. Rain up to 1,500' is possible and we have .2-.4" of it with 2-4" of snow in the Alpine. The snow at the mid-elevations is wet and saturated. These are prime conditions for triggering a wet loose avalanche on steep slopes. To initiate a wet loose slide the slope has to be quite steep, but once it starts moving can gain a lot of momentum and run to valley bottoms. Steering clear of steep slopes with 'boot-top' wet snow is an avalanche forecaster's rule of thumb.


Mountain Weather

Partly cloudy skies with some blue holes covered the region yesterday. Light precipitation fell, adding ~.2" of rain below 1,000', and was mostly centered around Turnagain Arm. Around 2" of snow has fallen in the past 24-hours above 1,500'. Temperatures dropped to 32F at 1,000' and are holding steady in the mid 20's on the ridgelines. Winds have been sustained in the moderate range with averages 20-25mph from the East along the ridgetops. 

For today, we are expecting mostly cloudy skies along with light precipitation. Between .2-.4" of rain is expected to fall below 1,500 with 2-4" of wet snow above this. The rain/snow line is currently around 800' this morning but looking to climb a bit through the day. Ridgetop winds are expected to remain moderate from the East, 20-25mph. Temperatures remain warm, mid 30's F at 1,000' and mid 20's F at 3,500'.

For Monday we remain in this unsettled warm and showery pattern, but for Tuesday we could see cooler temperatures and a real break in weather. 

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880')  32  0.3 104 
Summit Lake (1400') 34   0 30 
Alyeska Mid (1700') 33  1.5   0.15 84 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 24  NE  22  54 
Seattle Ridge(2400') 27 

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
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