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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Thursday, February 11th 2016
Created: Feb 11th 6:20 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'
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Special Announcement

This Saturday Hatcher Pass Avalanche Center and Friends of the CNFAIC are joining forces to support FREE avalanche education at Hatcher Pass and in Palmer. There will be a FREE companion rescue workshop on Saturday, February 13th, 10:30am-12:30pm, Hatcher Pass Gold Mint Lot and a FREE avalanche awareness class Wednesday, February 17th, 6:30-8pm, Palmer High School Library. Click HERE for more information!


The Bottom Line

The avalanche danger is MODERATE for both wet avalanches and glide avalanches at elevations between 1,000' and 2,500'. This is due to rain-on-snow that is weakening these mid-elevation bands. Above 2,500', in the Alpine terrain, we have a MODERATE avalanche danger for wind slab avalanches. Fresh wind slabs up to a foot, or more, thick will be possible to trigger on steep slopes with wind deposited snow.


Primary Concern

Rain to 2,000', or higher?, say it isn't so.... We have squeaked through the season so far with good snow coverage at the road elevation at 1,000', but today it will be raining. Our snow coverage should remain mostly intact, but things will be wet and soggy out there. We are expecting .5" of rain up to 2,000-2,500' with roughly 4-6" of dense snow above 2,500'. Hence, wet avalanches and glide avalanches will be our primary concerns. 

WET AVALANCHES:
At the mid-elevations wet loose avalanches should be expected today with rain-on-snow. These could release naturally or be triggered by a person or snowmachine on a slope. Even a small wet loose slide can entrain a significant amount of snow and become large and dangerous on long steep slopes/gullies. There is also the possibility we could see a few wet slabs, these are likely to be triggered by a wet loose slide running over from above. If you do head out today, keep an eye on steep slopes in the rain. 

GLIDE AVALANCHES:
The warm temperatures and wet weather could initiate another glide cycle. Or at least, get a few more 'looming cracks' to avalanche. Anyone that has been in the Turnagain Pass area knows hundreds of glide cracks littler the slopes. Avoid being under these - today especially!


Secondary Concern

In the Alpine, where it is snowing and blowing, you can expect to see fresh wind slabs up to a foot deep. We have had 2-3" of new snow overnight with another 4-6" on the way today. This new snow is expected to be dense and quite sticky due to the warm temperatures. This set up usually allows these fresh wind slabs to stabilize relatively quickly. That said, if you find yourself in avalanche terrain today at the high elevations, watch for wind loaded areas, cracking in these spots and of course any recent avalanches. Wind slabs are most easily triggered while, and just after, forming.


Additional Concern

In areas outside of our core forecast zone, including South of Turnagain Pass and the Summit Lake area, the snowpack is shallower and harbors various weak layers; the most notable weak layer is a layer of buried surface hoar 2-3' deep in the pack. We have found these to be unreactive in the past week but with today's warm weather, they could re-activate. For more information see this report from the Lynx Creek drainage and this avalanche triggered January 30th

 


Mountain Weather

Mostly cloudy skies covered the region yesterday as a weak low-pressure system is over us currently. We had only a few light snow/rain showers with a rain/snow line around 1,200'. Winds were blowing ~15mph with gusts in the 30's from the East on the ridgetops. Temperatures were mild, in the mid 30'sF at 1,000' and the upper 20's at 3,500'.

Overnight, precipitation has increased slightly and we have picked up .25" of rain at 1,000' with 2-3" of snow above 2,500'. We are expecting another .5" of rain up to 2,000' today and 4-6" of snow at the higher elevations. This is one of the highest rain/snow lines we have seen this season. Winds are forecast to blow strong along the peaks and ridgelines, 30-35mph with gusts in the 60's. Temperatures will be warm....up to 30F at 3,500' and 40F at 1,000'.

For Friday and into the weekend this warm and unsettled weather pattern looks to remain over us. However, as is usually the case, we could see some breaks in cloud cover and sunshine poke through here and there. 

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 34  Slush  0.2  107 
Summit Lake (1400') 35  31
Alyeska Mid (1700') 33  0.3 slush  0.45  90 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 27  NE  20  58 
Seattle Ridge(2400') 28   -  -

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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