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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Thursday, March 29th 2012
Created: Mar 29th 6:56 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
Good morning. This is Wendy Wagner with the Chugach National Forest Avalanche Information Center on Thursday, March 29th at 7am. This will serve as 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).

BOTTOM LINE
Pockets of CONSIDERABLE danger exist above treeline for wind slab avalanches. These are most likely found on West, South and Northerly aspects where slabs formed during the past 24-48 hours may be sitting on buried surface hoar. Pockets of CONSIDERABLE danger also exist at the lower elevations for wet avalanche activity due warm temperatures and rain on snow. CNFAIC Staffwise, there is generally a MODERATE danger for the Turnagain Pass area.

AVALANCHE DISCUSSION
After quite the remarkable cold winter, which has kept excellent dry snow to sea level, it seems the imminent spring warm-up is upon us. Warm temperatures and rain the past two days are wilting our below treeline snowpack and wet saturated snow exists below 2000' while dry snow remains above treeline. Yesterday's avalanche activity was relegated to minor wet loose slides below treeline with fresh wind slabs forming above.

Below treeline - Wet Avalanches
With rain on snow below 1000' and wet saturated snow below 2000', wet avalanche activity will be a concern for those traveling in the lower elevations. Wet point release avalanches on all aspects (not just southerly as we have been seeing with sun effect) are possible to release on their own today. These have the potential to entrain a lot of wet snow as well as a chance for triggered a deeper slab where buried weaknesses exist.

Above treeline - Wind Slab
The strong to moderate winds during the last 48 hours have been loading slopes near and above treeline. Yesterday, we found that not all, but some, of these recent slabs are sitting on surface hoar in highly traveled locations, making for a touchy wind slab problem for those venturing out of the wet snow to the upper elevations. Careful evaluation of the upper pack is necessary above treeline, as triggering a stiff wind slab could break above or adjacent to you, taking you for a ride.

Cornices and Glide Avalanches
With the warm temperatures, watch for cornices to loosen up and begin pulling away from the ground forming larger 'cornice crevasses' or break off all together. Additionally, staying out from under opening glide cracks is advised as many of these are beginning to open up; one did just release south of Devil's Pass (south of Summit Lake).

Persistent Slab
The two old buried weaknesses (surface hoar and facets around sun crusts buried 3/15) still reside 2-3' deep in some areas. Though we have not seen an avalanche break into these deeper layers for several days, with the warm temperatures they could become reactive again and warrant mention.

MOUNTAIN WEATHER
After a warm, wet and windy morning yesterday, skies broke up by mid-day and temperatures rose into the upper 40'sF at 2000' and 30's on the ridgetops. The rain/snow line has crept up and is hovering just above 1000' currently. Above treeline, snow that fell Tuesday through Wednesday accumulated to a whopping 15" in the Girdwood Valley and only 3-5" on Turnagain Pass. Winds the past 24 hours have been strong from the east on the ridgetops, sustained in the 25-35mph range and gusting in the 40's and 50's.

Today, the scattered light rain/snow that is falling this morning may add anCNFAIC Staff few inches of snow up high but diminish with breaking skies possibly later in the day. Temperatures that dropped slightly overnight should rise again into the 40's below treeline and 30's above. Easterly winds are forecast to continue but decrease a touch, sustained between 15-20mph with gusts between 35-40mph.

CNFAIC Weather Page and the NWS forecast

Kevin will issue the next advisory Friday morning. If you get out in the backcountry we want to know what you are seeing. Please send us your observations using the button at the top of this page or give us a call at 754-2369. Thanks and have a great day.

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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