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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   John Fitzgerald  
Monday, January 21st 2013
Created: Jan 21st 5:55 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.
2 Moderate Treeline / 1,000'-2,500' Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
2 Moderate Below Treeline / Below 1,000' Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
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The Bottom Line

Today the avalanche hazard is MODERATE above treeline.  A moderate amount of new snow and wind has created slabs that will be sensitive to human triggers.  The possibility still remains for large and destructive avalanches to be triggered in the higher elevations today.  The hazard below treeline is LOW this morning and will rise to MODERATE, as rising temperatures will slightly increase the chances for humans to trigger avalanches today.


Primary Concern

Recent snow in the higher elevations have fallen on slick and hard surfaces.  While the snowfall amounts have been modest, the winds overnight have been transporting this snow onto leeward aspects, mainly West to North facing slopes.  With temperatures forecasted to increase throughout the day, expect these slabs to become more sensitive to human triggers.  Expect to see shallow pockets of windslab at mid elevations (up to 1800') in open areas to be the most sensitive today, as these slabs have fallen on a firm crust and will heat up more readily than slabs in the higher elevations today.  On the flip side, these slabs are not as large (<6") as slabs in the upper elevations (>12").  Avoiding steep upper elevation starting zones which have a pillowy or wind affected look will also be important, as these slabs, once released, have the potential to carry people downslope and into terrain traps today.


Secondary Concern

It is important to not forget the poor structure of the base of our snowpack.  Snowpit tests over the past week continue to show weak faceted snow persisting near the ground.  The large dense slabs that formed over the holidays are now able to support a lot of weight.  The chances of initiating one of these slabs is getting more difficult by the day.  If you were to trigger one of these deep slabs, the outcome would be bad, as the volume of snow could be very large.  We are clearly in a dormant period for this avalanche problem, as it has been a week now since any new deep slab activity has been reported.  Unfortunately, the weak snow is being well preserved in many areas and will continue to lurk well below the surface for the forseeable future.  Staying away from areas showing exposed rocks, ground or vegetation will be important in avoiding this problem today, as these are the most likely areas to trigger a deep slab avalanche.


Mountain Weather

In the past 24 hours Turnagain Pass has received ~6" of new snow with .3-.5" water equivalent. Winds have been moderate out of the E and SE averaging 20 mph with gusts to 36 mph.  Temps, which have been on a steady rise overnight have averaged near 32 F at 1800', and in the mid 20s F at 3800'.
Expect clouds to be on the increase through the day, winds out of the East 20-35 mph and a chance of precipitation with up to 3" of new snow possible in the mountains.  Temperatures will climb into the mid 30s F at 1000'.
The extended outlook calls for a greater chance of snow tonight, with precip continuing into the middle of this week.

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Wendy will issue the next advisory, tomorrow morning January 22nd.

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: Apr 11, 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: OpenWide swaths of open river in the Placer Valley. Travel with extreme caution!
Skookum Drainage: ClosedSKOOKUM DRAINAGE CLOSED TO MOTORIZED USE ON APRIL 1 annually as per the Chugach National Forest Plan document.
Turnagain Pass: Open
Twentymile: ClosedClosed for the remainder of the 2017 season.
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.


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