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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Saturday, March 5th 2016
Created: Mar 5th 6:57 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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The Bottom Line

A MODERATE avalanche danger exists in the Turnagain Pass area today for wind slab avalanches, glide avalanches and cornice falls. Watch for fresh wind slabs to be forming in the 3-5" of new snow expected with moderate to strong winds. These slabs are likely to be around 6-10" thick and forming at the upper elevations. At the mid-elevations, glide cracks continue to release and limiting time under these is prudent. Last, give cornices a wide berth and limit time under them as well. 

Today is a day to watch the changing weather conditions and take inventory of the new snow amounts. There is a possibility this system could turn out to be a 'sleeper storm'; meaning we receive more snow than forecast. 

*If you are headed to the Summit Lake area don't forget to check today's Summit Lake Summary and click HERE for recent Summit Lake observations.


Primary Concern

A weak storm system has entered the Eastern Turnagain Arm region this morning. Snowfall has just begun and Easterly winds have just picked up. We are expecting 3-5" of snow today above 1,000' with rain below (this rain/snow line could creep up through the day and we could see more than 5" of snow in places). With this new snow and ridgetop winds in the 15-30mph range, we can expect shallow wind slabs to be forming. These slabs will be sitting on this past week's variable surfaces (sun crust, wind crust, soft settled powder). How well the fresh slabs will bond with the old surfaces will be the question today.

If you are headed out pay close attention to:
1)  How much snow has fallen.
2)  What are the winds doing. Are they transporting snow along the ridgelines? Are they loading slopes?
3)  How well is the new snow/wind loaded snow bonding with the underlying surface? Quick hand pits can be good to suss this out.

Cornice falls:  As is the general rule, these are worth avoiding/limiting time under as they continue to break off. Today they will get stressed a bit more with new snow and wind.

Photo below: Pete's North ridgeline from yesterday. Recent cornice falls can be seen along the ridge. 


Secondary Concern

Although we have a short burst of snowfall and wind on tap today, glide avalanches remain just as much of a concern. This is due to the countless number of glide cracks in places folks recreate and the destructive nature of a glide avalanche in the event one does release. There were several glide cracks that slide yesterday in the Summit Lake area and one possible new glide avalanche in the Lynx creek drainage. All that said, it's worth keeping a lookout for cracks and minimizing time under them - no question! 

Photo from yesterday: Very large glide crack on the SW face of Cornbiscuit. You can see tracks on the looker's left of the 8-12+' deep crack.


Mountain Weather

Partly sunny skies, with some blue holes, covered the region yesterday. A morning snow squall added a trace of snow at sea level in Girdwood (and a few inches in Anchorage - causing some driving mayhem) but this all missed Turnagain Pass. However, snowfall has started to fall this morning and as of 6am we have seen 2" accumulate. Winds during the past 24-hours have been steady averaging ~10mph with gusts to 20mph. Temperatures have been in the mid 20's F on the ridgelines and ~30F at 1,000'. 

Today we have a weak system moving over us from the East. This will give us a chance for 3-5" of snow with a rain/snow line between 1,000 and 1,500'. Temperatures should climb through the day and peak around 35F at 1,000' and the upper 20'sF on the ridgelines. Winds are slated to bump up to the moderate-to-strong category from the East along the ridgetops (15-30mph with stronger gusts).

This system looks to exit this evening and tomorrow, Sunday, we should see party sunny skies with a possible snow shower here and there. Stay tuned.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 25  0.2  139 
Summit Lake (1400') 25  42 
Alyeska Mid (1700') 25  0.15   104

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 24  NE  23 
Seattle Ridge(2400') 26 

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

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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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