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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Tuesday, February 4th 2014
Created: Feb 4th 6:32 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.
1 Low Treeline / 1,000'-2,500' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
1 Low Below Treeline / Below 1,000' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
 Show the Complete North American Avalanche Danger Scale
The Bottom Line

The majority of terrain in our forecast zone continues to have a LOW avalanche danger. The exception is the elevation band above 3-3,500' where dry snow exists. At this uppermost elevation there is a MODERATE danger for triggering a deep slab avalanche, wind slab or potentially a shallower slab sitting on faceted snow 1-2' deep.

Below the 3-3,500' elevation band where the danger is LOW a very hard crust is present creating slippery slide-for-life conditions.


Primary Concern

Though the majority of terrain in our forecast zone is below 3,500' and frozen solid as a rock, there are areas, like Pastoral Peak, that are high enough to have dry snow. At these locations there is an old weak layer of facets (the November snow) buried 3-6+' deep. Although this layer is buried fairly deep and has had a week or more to adjust to the load placed on it during January, it is still there and therefore a concern. If someone finds just the right thin spot and a deep slab is triggered it could produce a large and destructive avalanche. The likelihood for this is low but the consequences can be high. 


Secondary Concern

Keep an eye out for old and stiff wind slabs at the high elevations and peaks. Though the wind has picked up a bit during the past 24-hours to the 10-15mph range with gusts into the 30's there is little snow to transport. However, as with any travel in exposed areas with dry snow, finding a wind slab can be possible.


Additional Concern

Another concern that may be developing at the very upper elevations in the dry snow (above 3,500') is faceting surrounding one or more crusts. This is in the top 1-2 feet of the snowpack. During the tail end of our wet January weather (Jan 26-28) the rain/snow line fluctuated around 4,000' and we know there is at least one crust that was formed up to 4,500+'. This is 6-8" below the surface and was seen on January 30th - more details can be found HERE. With almost a week now of clear and cool weather I wouldn't be surprised to find facets developing around the crust. If this is the case, triggering a slab avalanche breaking in a weak layer near a crust could be possible. This is something to think about and look for if you are venturing to the uppermost elevations.

If anyone does head up to these areas, we want to know what you are seeing - send us an observation!


Mountain Weather

During the past 24-hours we have seen mainly overcast skies and mild temperatures. Ridgetop temperatures have averaged in the low 20's F and the mid 30's at sea level. Ridgetop winds have been mainly from the East with averages in the 10-15mph range with gusts to 30mph.

Today we should see cloud cover begin to clear and possibly some sunshine. Temperatures look to drop a hair today with highs around 20F on the ridges and 30F at sea level. Ridgetop winds should remain in the 10-15mph range from the Southeast.

Looking to the latter part of the week we have a chance for a few flurries to a few inches of snow on Thursday night into Friday. This is associated with a small system developing over PWS. Along with the potential snow, winds will be increasing and we will return to our blocking high pressure for the weekend. The NWS has posted a Special Weather Statement - though you may not want to read it...

 

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: Mar 25, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: OpenPlease park on road in and leave the turnaround (near outhouse) open for trailers to turn around.
Placer River: Open
Skookum Drainage: OpenSkookum drainage closes to motorized use on April 1 annually as per the Chugach National Forest Plan document.
Turnagain Pass: Open
Twentymile: Open
Seward District
Carter Lake: Open
Lost Lake Trail: OpenPlease STAY ON existing and hardened trail surface through the lower sections of this route.
Primrose Trail: OpenPlease STAY ON existing and hardened trail surface through the lower sections of this route.
Resurrection Pass Trail: ClosedClosed for 2016/17 winter season. This is a non-motorized season. This alternates every other year and will open again during the 2017/18 winter.
Snug Harbor: Open
South Fork Snow River Corridor: Open
Summit Lake: Open

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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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