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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Kevin Wright  
Thursday, March 13th 2014
Created: Mar 13th 6:43 am
4 High Alpine / Above 2,500' Travel Advice: Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.
4 High Treeline / 1,000'-2,500' Travel Advice: Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.
4 High Below Treeline / Below 1,000' Travel Advice: Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.
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Special Announcement

Turnagain Pass is again OPEN to snowmachines.  The recent storms have provided enough snow cover to prevent resource damage.


The Bottom Line

It's another storm day!  8 inches has fallen overnight at Turnagain Pass and we could get another 20-30 inches in the next 24 hours.  

The avalanche danger will start this morning at CONSIDERABLE and rise to HIGH as the day progresses and snow builds.  

Yesterday we saw very little natural avalanche evidence from our Monday storm, which dropped 2 feet at the Pass, but collapsing of the snowpack was frequent when breaking trail.  All the new snow from this week is poorly bonded to the February crust layer.  With a lot more snow forecasted today, avalanches could be breaking 4 feet deep to the crust, making them unmanageable and dangerous.  

Safe travel today will require staying away from all avalanche terrain, including runout zones.


Primary Concern

There are 2 interfaces in today's snowpack that may act as sliding layers.  They can be separated out by the 2 storms we've seen this week.

Storm snow that started falling last night may slide at the old surface layer we were skiing on yesterday.  Yesterday we had a sunny break in the weather that built sun crusts on southerly aspects.  With new snow building, this could become a sliding interface.  

This morning the new storm snow is less than a foot deep, but is expected to reach closer to 2 feet by the end of the day.


Secondary Concern

Monday's storm fell on the old February crust, which has some buried surface hoar acting as a weak layer above the crust.  Yesterday we experienced frequent collapsing (whumphing) on this layer at elevations between 1000 and 2500 feet.   Some avalanche activity on Tuesday was reported up to 2 feet deep from this storm. 

A worst case scenario today would be avalanches that slide 3-4+ feet deep at the crust interface.  This would include snow from both storms this week.  


Mountain Weather

The storm that ended Tuesday dropped about 2 feet of snow in Girdwood and Turnagain Pass.  That snow transitioned to rain at lower elevations at the end of the storm.  

This morning, Center ridge weather station has already recorded about 9 inches of snow and up to 0.8 inches of water equivalent.  Sunburst station saw wind gusts to 105mph overnight from the East.  

Snow/rain line is predicted to stay at sea level today, but temperatures are right on the threshold.  Some rain is possible at sea level.  Snow above 1000 feet is expected to reach 11-16 inches today and another 9-14 inches tonight.  An east wind will stay strong while this storm continues.  

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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