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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Tuesday, January 29th 2013
Created: Jan 29th 6:51 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

Above treeline, the addition of 2-4 inches of snow with sustained easterly wind will keep our avalanche danger at MODERATE today for wind slab avalanches. These will be most pronounced on upper elevation steep slopes and in the 4-12" thick range. Watch for these fresh slabs to be sensitive to human triggers. Below treeline the danger remains LOW where only 1-3 inches of snow is expected to fall on a stout crust. It is unlikely, but in the case snowfall rates pick up and more than a few inches falls below treeline, expect the danger to rise to MODERATE as the new snow, and subsequent wind drifts, will not bond well to the crust.


Primary Concern

It was a fairly quiet day in the backcountry yesterday. We did not see or hear of any avalanche activity, nor were there too many folks out watching last weekend’s clear skies fill with clouds. We did get one report of soft wind slab conditions found in steeper north facing terrain.

Today, moderate to strong easterly winds accompanied by a few inches of snow is on tap. Fresh wind drifts and slabs will be forming on the lee side of ridgelines and in catchment zones mid-slope. These are likely to be sensitive to human triggers but in the shallow range (4-12”) due to the modest amount of new snow and the limited existing snow available for transport. Keeping an eye out for smooth rounded surfaces, stiff feeling snow and shooting cracks will be key to avoiding triggering a wind slab avalanche.

Below treeline a stout crust exists on the surface where the few inches of new snow today will likely get blown around and drifted into pockets. These pockets should be quite small but at the same note, will have a hard time sticking to the crust. In the case snowfall amounts increase to more than a few inches, watch for these small drifts to become larger and more worrisome.


Secondary Concern

The deep slab avalanche problem remains in the back of our heads. We are still concerned that in shallow areas above treeline there is a chance a person could trigger a slab avalanche breaking in the weak snow near the ground. Keeping with good travel practices – exposing only one person at a time, moving efficiently through steep terrain and steering clear of shallow areas near rocks is the best bet for avoiding one of these larger and more dangerous slides.


Mountain Weather

Cloudy skies, rapidly warming temperature and scattered snow showers have moved in overnight. This has quickly replaced the cold and clear weather that dominated the weekend. Overnight, Girdwood Valley and the Turnagain area picked up 1-2” of low density snow but the snow showers are tapering off this morning. Temperature is on the rise at all elevations - ridgetops have gone from -10F to ~+10F in 24 hours while lower elevations have seen a jump from ~-15F to +15-25F. The easterly wind that is responsible for bringing in the warm air has been in the 10-20mph range gusting near 40mph.

Today, snow flurries will continue but look to only add another inch or two in favored locations - for a total of 2-4” of new snow. Temperatures look to top out in the mid to upper teens at ridgetops today and the mid to upper 20’s below treeline. The easterly wind will remain in the 15mph range with gusts to 40mph.

Wednesday and Thursday will see cloudy skies, increasing temperature and a better shot for snow accumulation. We should see snow at sea level today but this will turn to a rain-snow mix Wednesday.

 


Kevin will issue the next advisory tomorrow morning, January 30th.

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
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