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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Sunday, January 25th 2015
Created: Jan 25th 5:45 am
1 Low Alpine / Above 2,500' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
1 Low Treeline / 1,000'-2,500' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
0 NO RATING Below Treeline / Below 1,000'
 Show the Complete North American Avalanche Danger Scale
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The Bottom Line

A generally LOW avalanche danger exists in the mountains surrounding the Eastern Turnagain Arm. The one exception will be pockets of MODERATE danger on upper elevation slopes for fresh wind slabs due to a bump in Northwest winds in specific locations. The most suspect areas are the Southeast face of Seattle Ridge and the Summit Lake zones. Any slabs that do form are expected to be shallow (6-8" thick), soft, easy to identify and avoid.


Primary Concern

A clear and very cold day is on tap today after a high-publicized snow event moved out yesterday. Despite a lot of cheering, our region came in near the end of the snow total race - seeing only few inches of new snow since Thursday. That said, low snow cover hazards remain below 2,000' - hitting rocks, hooking alders, slipping on overflow ice, etc. But, there is fun skiing and riding to be had at the upper elevations! Keep in mind, many areas have a hard and slick surface under the top 4-6+" of loose snow which can make travel up, or down, in very steep terrain challenging.

Things to watch for if you are headed to the mountains:

Wind Slabs
Northwest winds picked up yesterday along Seattle Ridge and have continued to blow in the 15mph zone overnight. With several inches of loose snow available for transport, not only will these winds do some damage to riding conditions but also may form wind slabs on leeward slopes in the 6-8" category. The Southeast face of Seattle Ridge is suspect along with other areas that may be affected by the Northwest winds. Any slabs found should be shallow, soft, drifted into pockets, easy to identify and avoid. Watch for smooth rounded surfaces and cracking in the snow around you. Before jumping into a line, sussing out the potential for a wind slab will be key.

Loose snow avalanches
Watch your sluffs on steep sustained slopes (> 40 degrees). These should be fairly low volume - composed of the top few inches of the snow.

Glide Avalanches
Glide cracks loom over terrain folks are traveling and avoidance is not always possible. However, limiting time spent under these - not stopping for lunch for instance - remains prudent, despite the cold temperatures.

Cornices
Cornices are hard and may pull back further than expected if you are traveling over them or messing around with them. 


Mountain Weather

Mostly cloudy and obscured skies covered the region yesterday as light snow showers moved out. Girdwood picked up 2" of new low density snow in the past 24-hours and Turnagain Pass an inch - making storm totals 4 and 2" respectively. General flow direction (Southwest) with this storm favored the Anchorage area and North, such as Hatcher Pass. Winds were light from the East until shifting to the Northwest mid-day ushering in cold air. 

Overnight skies have cleared and temperatures have PLUMMETED! Check out the graph from Sunburst below. A 29 degree drop in temperature in less than 36 hours - a legitimate puffy clothes day today for the first time this season. Currently, winds are 10-20mph from the Northwest and should be on a slow decline through the day. Temperatures should stay in the single digits at all elevations with skies remaining clear.

Sunburst weather station ridgetop data ending at 6am this morning:

 

Tomorrow, cold and mostly clear conditions will prevail ahead of another low pressure system forecast to move in from the West mid-week. This looks to have cold air entrained, which is good for a low snow line, but models are showing most of the precip staying to our South and East - however that can all change as we get closer.

*Seattle ridge wind data below is 10pm-6am.  The wind sensor was rimed.

PRECIPITATION 24-hour data (6am - 6am)

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 12  .1  31 
Summit Lake (1400') 11 
Alyeska Mid (1700') 13  0.15  23 

 

RIDGETOP 24-hour data (6am - 6am)

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812')  7  NW 20 
Seattle Ridge(2400')  8 12  35 

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 28, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Closed
Placer River: Closed
Skookum Drainage: ClosedSKOOKUM DRAINAGE CLOSED TO MOTORIZED USE ON APRIL 1 annually as per the Chugach National Forest Plan document.
Turnagain Pass: OpenOpen thru May 14th.
Twentymile: Closed
Seward District
Carter Lake: OpenClosed May 1.
Lost Lake Trail: OpenClosed May 1.
Primrose Trail: OpenClosed May 1.
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: OpenClosed May 1.
South Fork Snow River Corridor: OpenClosed May 1.
Summit Lake: OpenClosed May 1.

Subscribe to the Turnagain Area Avalanche Advisory:

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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