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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Sunday, December 30th 2012
Created: Dec 30th 6:39 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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The Bottom Line

Dangerous avalanche conditions remain in the backcounty. A strong pacific storm bringing rain, snow and strong wind will keep the avalanche danger HIGH. Human triggered avalanches are very likely both above and below treeline and natural avalanches are likely. Anything, or person, in an avalanche path, including the runout zone, is at risk. Travel in avalanche terrain is not recommended.


Primary Concern

Rain on snow will impact the below treeline areas today as this storm is bringing in warmer temperatures with rain up to 1500ft and heavy, wet snow below 3000ft. It is downright soggy on Turnagain Pass. This will be a good shock to the snowpack as it is the first significant load with warm temperatures at the mid-elevations. Natural avalanches are likely to release and send debris down gullies and into runout zones. There were 3 of these natural slides 24 hours ago on the front (east) side of Seattle Ridge - two of them covered highmarks across from the Turnagain Pass motorized lot. Today is not the day to play anywhere near or under slopes. In fact, it is a good day to stoke the fire and hunker down.


Secondary Concern

For the past week now we have seen several "Alaska style" storms that are putting down dense snow that is quickly bonding to itself. This normally would be a good thing, but this year the tabels are turned. The problem is we have a "Colorado style" base of weak faceted snow sitting underneath all this sticky Alaska snow. This has set the stage for the deep slab problem that will haunt us for a while. As of yesterday, we had a strong slab 3-6’ thick overlying 1-2' of weak snow from October and November. Today, we will add another couple feet to that - making it a 4-7’ slab. Any avalanche triggered with a slab this thick is unmanageable and likely unsurvivable.

As far as storm snow concerns go, such as fresh wind slabs and instabilities within the new snow, they are out there at the upper elevations. However, the wet avalanche and deep slab problems are the most concerning today.

 


Mountain Weather

It has been six full days now with accumulated precipitation and varying degrees of strong east winds. Today the onslaught intensifies with a powerful storm churning in the Gulf. This is ushering in warmer temperatures with rain falling below 1500’. We can expect around 2 – 2.5” of rain (20-30” of dense snow above treeline) from overnight into this evening. So far this morning we have around 0.5" of rain on Turnagain Pass with 1" at mid elevations in the Girdwood Valley. Wind has been relentless from the east and is averaging 60mph with gusts over 100mph – which should remain though the day. Ridgetop temperatures are, and will continue to be, in the mid to upper 20’s F and mid to upper 30’s below treeline.

We are in a nice progressive pattern and should see a break Monday with another low moving in for Tuesday. This system looks to be a bit cooler but fairly potent.


Fitz will issue the next advisory on Near Year's Eve - Monday morning, December 31st.

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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