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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Graham Predeger  
Thursday, January 17th 2013
Created: Jan 17th 6:50 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 tree line elevations the avalanche danger remains MODERATE today.  The more time we can put between now and this most recent bout of wet storms the less likely it will be to trigger an avalanche.  However, large avalanches are still possible in isolated areas given the widespread buried persistent weak layers present in our pack.  Below tree line the danger is LOW.


Primary Concern

The deep slab issue continues to be our primary concern today in the backcountry and won’t be going away anytime soon. Terrain management becomes particularly important when dealing with persistent weak layers and also happens to be the toughest skill to master for mountain professionals the World over.  Today and for the rest of the season it will be prudent to expose only one person at a time to avalanche terrain and don’t park or hang out in run out zones.

Though the likelihood of triggering a deep slab avalanche is decreasing with time, overlying slabs are still showing the potential to propagate if a fracture is initiated.  Likely areas to initiate a fracture may be near trigger points such as rocks or trees mid-slope where the slab is shallow or interrupted.  We’ve seen numerous examples since the New Year of the destructive potential these large avalanches can harbor, and in the case of Repeat Offender last week, that particular avalanche was triggered remotely from a shallow trigger point.

The best surface conditions for skiing and riding today will be found above ~1500’ in areas where the snow is deep and consistent.  Below 1500’ the surface consists of a few inches of new snow over a stiff crust capable of supporting a snowmachiner.  This crust, formed by Sunday’s wet storm and subsequent cold temperatures could prove a future weak layer at lower elevations once overlain by a slab.


Mountain Weather

Looking at snowfall totals around south central, Anchorage and Hatcher Pass (~12") both appear to be eeking out a bit more snow than the Turnagain pass/ Girdwood region due to the up-sloping nature of this latest front.

Today we can expect light winds from the north and west with snow tapering off this afternoon (24 hour accumulation of less than 6").  Temperatures will stay below freezing at all elevations as skies clear throughout the day. Looking out toward the weekend it appears we may be back into an active pattern of weather.

 

Fitz will issue the next advisory tomorrow morning, January 18th.

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
If you have comments or questions regarding CNFAIC operations or winter recreation management, please email staff@chugachavalanche.org
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