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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   CNFAIC Staff  
Sunday, November 19th 2017
Created: Nov 19th 15:10 pm
0 NO RATING Alpine / Above 2,500'
0 NO RATING Treeline / 1,000'-2,500'
0 NO RATING Below Treeline / Below 1,000'
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The Bottom Line

Today is Monday, the beginning of Thanksgiving week, and this will be one of our last updates before we begin issuing avalanche advisories! A quick moving storm added 2-6" inches of light snow to the mountains around Turnagain Pass, Girdwood and the Kenai yesterday. The snow depth at the Turnagain Pass SNOTEL station at 1,880' now reads 7" - that is pretty thin for Nov 20th. Generally speaking, the snow cover is shallow and variable. Snow depths above treeline range from 6" to 2'. There looks to be a low pressure system setting up to bring another round of snow for Thanksgiving through this weekend. Look for more on that Wednesday with our next report!

Today's avalanche concerns: 

Although the few inches of new snow from yesterday may be enough for small sluffs in steep terrain and may have been blown into small soft wind slabs, what the new snow is concealing is the most concerning:  Old hard wind slabs sitting on faceted snow.

Yes the snowpack is thin, but there are still slopes and gullies that collected enough wind blown snow from the last month to form a hard slab. These old slabs can pop and avalanche if they are sitting on weak snow below. This was the exact case on Saturday when a hunter was walking along a ridge near Carter Lake on the Kenai . The hunter collapsed the weak layer with his foot when getting off his snowshoes and penetrating through the slab. He was not on the slope, but the collapse propagated over the ridge and he remotely triggered an avalanche 75' away. Take a look at the image below. These old hard slabs could ruin your day quickly as even a small one can take you down a very unpleasant ride through rocks.

So for today and this week - the slopes with the most snow are the most suspect for one of these larger avalanches. The problem is, these are the slopes we will be drawn to as to avoid hitting rocks and ground with our skis and boards... The obvious RED FLAG clues may not be present, making your decision to ride a slope or gully more difficult. Digging in to see if the pack has a harder slab over weak facets is a great way to suss this out. But, know that pits don't always tell the story of the slope next to them. Keep these things in mind if headed to the mountains and remember avalanche season has started. Use safe travel protocol and know how to use your beacon, probe and shovel. 

 

 

Below are a few photos from Heather and Aleph's field day last week. Mentally paint  2-6" of very light snow on top and this will be a picture of what conditions are like now. 


Sunburst and Magnum


Seattle Ridge


Variable wind drifted snow on Tincan

 


Snowpack structure in area with shallow wind slab over facets

 


Primary Concern

Today's educational theme is GET THE PICTURE and it's the fourth of the five GETS. More on the GETS on the Know Before You Go video link.

Part of GETTING THE PICTURE and key to staying safe in the backcountry is recognizing RED FLAGS. Ask yourself: Have I seen any signs of recent avalanche activity on the drive to the trail head? Have I seen any on my route in the backcountry? Have I heard any whumphing? Is the snow sending out shooting cracks as I travel on it? Is the weather changing? Is it snowing rapidly? Raining? All these things are clues saying "you could trigger an avalanche today".

Many avalanche accidents can be attributed to people missing clues that indicate that the snowpack is unstable.

It is important to look for these RED FLAGS everytime you go out. 

  1) Recent avalanches

  2) Shooting cracks

  3) Snowpack collapsing (whumpfing)

Has something changed that could have stressed the snowpack?

  4) Recent snow or rain

  5) Recent wind

  6) Rapid temperature change

Use the Observation page: HERE and the Weather page: HERE, in addition to checking the Avalanche Advisory to help understand the picture before you go!

 


Mountain Weather

For weather information during these updates, see:

CNFAIC Weather Page

NWS Mountain Recreation Forecast 

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: Nov 18, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Closed
Placer River: Closed
Skookum Drainage: Closed
Turnagain Pass: ClosedOnly a few inches of snow sits at the motorized lot, not enough to open for snowmachining at this time. Updated Nov. 18, 2017
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

Subscribe to the Turnagain Area Avalanche Advisory:

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
© 2017 Chugach National Forest Avalanche Information Center. All rights reserved.
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