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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   John Fitzgerald  
Tuesday, December 2nd 2014
Created: Dec 2nd 6:55 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.
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
Special Announcement

Our first, in a series of four, Fireside Chats begins Thursday December 4th! These will be held in both Girdwood and Anchorage. Thursday night's Chat will be at 6:30pm at the Glacier Ranger Station in Girdwood. The topic will be - Intro to Avalanches: Terrain and route finding, presented by CNFAIC forecaster John Fitzgerald. Mark your calendar!


The Bottom Line

The avalanche danger is MODERATE today in the alpine, where newly formed wind slabs up to 10” in depth will be easy to trigger on steep leeward slopes.  At treeline the danger is LOW, with the exception of isolated wind loaded pockets in steep terrain.  Below treeline the snowpack is still too shallow to warrant a danger rating.

Early season hazards such as shallowly buried rocks, stumps and small glide cracks require careful travel, especially below treeline.

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The next advisory will be Thursday Dec 4th at 7am.

Avalanche Outlook for Wednesday: Expect wind slabs to continue to build at a modest rate through Wednesday.  A pattern of unsettled weather will bring some additional light snowfall and enough wind to keep the danger at MODERATE in the alpine for Wednesday.


Primary Concern

A modest amount of new snow combined with older low density snow and steady winds out of the East/Southeast have formed wind slabs on leeward aspects.  These slabs will be sensitive to human triggers and will be up to 10” in depth.  Expect them to be easiest to trigger as they are forming.  Keep in mind that while the predominant winds have been out of the East, wind changes direction as it interacts with terrain.  Your best bet is to be on the lookout for shooting cracks in the snow, upside down snow, or surfaces that are smooth and pillowy.  These are signs of recently formed wind slab.  Avoiding these wind loaded areas, especially in terrain over 35 degrees will be the best way to manage this avalanche problem today.


Mountain Weather

A large Low pressure system centered in the Bering Sea that has made its way eastward along the Aleutians has brought with it precip and winds to the mountains around Eastern Turnagain Arm.  Snowfall amounts have been greater to the West and less on Turnagain Pass.  Weather station data from the Girdwood Valley is currently unavailable.

A warm front associated with this Low has brought slightly warmer air over the area this morning.  Fortunately temps have remained cool enough to keep the precip in the form of snow. As this frontal boundary passes expect temperatures to cool and light snow to continue into the daytime hours.

Today we can expect another 3-5 inches of snow.  Temperatures at 1,000’ will be in the low 30s F.  Ridge top winds will be in the 10-20 mph range.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 25  2  .2  20
Summit Lake (1400')  24  3  .3  5
Alyeska Mid (1700')  n/a  n/a  n/a  n/a

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812')  19  E  13  30
Seattle Ridge(2400')  21  SE  18  37

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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