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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Sunday, January 5th 2014
Created: Jan 5th 6:42 am
4 High Alpine / Above 2,500' Travel Advice: Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.
3 Considerable Treeline / 1,000'-2,500' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
3 Considerable Below Treeline / Below 1,000' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
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Special Announcement


An Avalanche Warning remains in effect through today. Dangerous, unsurvivable avalanche conditions exist in the backcountry.


The Bottom Line

The avalanche danger is HIGH today at and above treeline. The addition of 12-14+” of new snow and strong wind is overloading weak snow near the ground. Large full depth avalanches 3+’ deep are very likely to be triggered by a person.  A CONSIDERABLE danger exists below treeline (below 2,000’) where triggering a slab avalanche 1-2’ deep is likely on steep slopes and rollovers.

Large avalanches can be triggered from a distance and from the bottom of a slope. Travel in avalanche terrain is not recommended. This includes runout zones from slopes above.

*Don't be fooled if the skies clear today, the avalanche danger remains HIGH. This is based mainly on the travel advice portion of the danger scale. The height of the storm has passed but our weak snowpack and recent large avalanche incidents give reason to be very conservative in our backcountry travel.


Primary Concern

Our tenuous snowpack is on the brink. During the past 24-hours we have added yet another load (1-1.5” of water equivalent). This may not sound like much for a coastal climate, but our snowpack has such a weak foundation that 12-14+” of new snow will impact it. The slab that overlies the weak faceted snow near the ground was around 2' deep yesterday and today will be around 3' deep.

There were multiple medium to large human triggered avalanches Friday. One of these claimed the life of a dog. A preliminary write-up can be found HERE. A party of a few skiers was able to initiate a collapse on a broad ridge and trigger 4 avalanches 50-300’ away simultaneously. Additionally, two large avalanches were remotely triggered in Seattle Creek. These avalanches are breaking in the weak snow near the ground and taking most of the snowpack along with it. The character of remote triggers and close to full depth slides is a scary combination. With this new load and warming temperatures expect avalanches to be easier to trigger and larger today.

 

Below is an image of the large Tincan avalanche from Friday. (Photo: Kevin Wright)


Secondary Concern

Instabilities within the new storm snow will be prevalent today but these issues are trumped by the bigger problem at hand - mentioned above. The new snow came in with both strong East winds and warming temperatures. This means there are both wind slabs from the wind and soft slabs from the upside-down nature of the storm. These new snow issues are in the top 1-2’ of the pack and will result in avalanches around 1-2’ deep. 


Mountain Weather

A wet, warm and windy storm has moved through the Easter Turnagain arm beginning yesterday morning and is now exiting. During the past 24-hours we have seen 12-14” of snow (likely more at the upper elevations) and rain below 500ft. Winds have been consistently strong from the East averaging 40mph with gusts up to 84mph. Temperature has been in the mid 20’s F on ridgetops and increased to the upper 20’s overnight with sea level temperature in the mid to upper 30’s.

Storm totals to date (beginning 7am yesterday, Friday 1/4):

Girdwood Valley (2800ft) – 14” snow (1.28” water)
Turnagain Pass (1880ft) – 12” snow (1” water)
Summit Lake (1400ft) – 2” snow (.1” water)

Today snowfall will taper off with a chance for 1-4” additional accumulation. However, the strong East wind will remain with averages near 40mph. Temperature also remains warm – upper 20’s on the ridgetops and low 30’s at 1,000’.

For tomorrow, a smaller system develops that could add 4-8” of snow. This looks to also be a warm and windy event.  Stay tuned.

 

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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