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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Wednesday, April 9th 2014
Created: Apr 9th 5:46 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.
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The Bottom Line

There is a MODERATE avalanche danger today on all aspects above treeline for small to medium sized loose snow avalanches and scattered 6-10" thick wind slab avalanches. Sluffs in yesterday's new snow should be predictable, expected and easy to trigger - on sunlit aspects, watch for these to turn to wet sluffs later in the day. 


Primary Concern

Yesterday was a reminder of what winter can be like. We ended up with 6-8" of very low density powder snow. Though it was enough to blanket the many tracks put down over the past month, it wasn't quite enough to keep your skis/board or sled off the old hard surfaces underneath. Today we have a fight to return to spring as the sun is expected to shine but the temperatures look to remain cold.

How much the sunshine is able to warm the new snow will be the main concern for today. Despite cold temperatures, if the wind remains light we can expect wet point release avalanches to occur on East, South and Westerly aspects as the sun makes its rounds. Watch for these to release both naturally from rocks and trees as well as be easy to initiate yourself (as seen in this VIDEO from yesterday). These could become fairly large on sustained slopes as all the new snow will likely be entrained on the way down. Dry sluffs on Northerlies or areas the snow remains cold should also be expected.

Wet or damp sluffs are much harder to get out of and can push you around much more than dry sluffs due to the heaviness of the debris. This is one of those predictable and easy to manage avalanche issues if you are aware of your terrain. Getting run over by a wet sluff in a confined gully can become a serious issue.


Garden variety new snow sluffs from yesterday - this will likely be the case again today:

 


Secondary Concern

Although winds were calm at many weather stations yesterday and overnight, the gap winds did blow strong up Turnagain Arm (from the West). Seattle Ridge weather station can feel some of these and had a few hourly averages near 15mph during the past 24-hours. Additionally, wind may bump up a bit today - enough to move a little snow around on the ridgelines. The new snow is so light that it won't take much to form soft wind slabs. If you are in one of these more windy locations, watch for cracking in the snow around you and surface clues that wind has formed slabs. These should be shallow and soft but also could have enough volume to be a problem if you are in larger terrain and significant snow is entrained.


Mountain Weather

Yesterday turned out to feel quite winter-like with 6-8+" of new snow, cold temperatures and mostly obscured skies. During the past 24-hours we have seen temperatures average in the low teens on the ridge tops and the mid 20'sF at 1,000'. Winds have been very light from the Northwest averaging 3-5mph, the exception is along Turnagain Arm mentioned above.

Storm totals at treeline are:
   Turnagain Pass:  6-8"
   Summit Lake:  1"
   Girdwood Valley:  6-8"

For today, skies should clear this morning and the sun will be out as a high pressure builds over mainland Alaska. Temperatures have plummeted to the single digits on the peaks overnight but should rebound a bit with daytime heating. Winds are slated to pick up slightly from the Northwest to the 10-15mph range.

Thursday and Friday the high pressure remains with sunny skies on tap. However, for the weekend it looks like another low pressure may move through.

 

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 28, 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: OpenPlacer remains open but SKOOKUM DRAINAGE will close to motorized use on April 1st.
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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