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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Heather Thamm  
Friday, March 6th 2015
Created: Mar 6th 6:09 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

Tonight at Midnight Sun Brewery from 5-7:30pm, The White Out Gallery and 19 very talented and generous Alaskan artists have come together to host a month long art show and auction, as a fundraiser for the Alaska Avalanche School. The funds will go to the Know Before You Go youth education program and the Instructor Development Fund.


The Bottom Line

Much of the terrain in Turnagain Pass has a LOW danger where triggering an avalanche is unlikely. However there are areas in the Alpine, above 2500’, where the avalanche danger is MODERATE and triggering a slab 1-2’ is possible. This will be more likely in steep complex terrain, like on large unsupported slopes, around steep rocky features and in steep gullies. 


Primary Concern

In the Alpine a slab 1-2' thick is sitting on a old weak layer of snow, but over the last 10 days triggering this slab has become more difficult with time. Very few obvious signs of instability have been observed over the last week, and inconsistent test results help point towards this weak layer adjusting to its load. On the flip side, we are still finding propagation potential in places, causing enough uncertainty to still encourage conservative slope choices. This problem seems to be more reactive on slopes with more of a Southern aspect where a sun crust/facet interface exists.

Obvious clues such as collapsing/woomphing may not be present and triggering a slab may require steeper terrain or a larger trigger, like several people on a slope. Be sure to practice safe travel habits. Identify safe spots, move between islands of safety one at a time, and always have an escape zone in mind.

Overnight only a trace of new snow fell in Turnagain Pass above 2000’ and another wave of precipitation is expected tonight into Saturday morning. Unfortunately for Turnagain Pass the direction of this cold front looks to be favoring the Talkeetna Mountains. If heading to Hatcher Pass this weekend, be sure to check out the Hatcher Pass Advisory updated once per week on Saturday mornings. 

A stout melt/freeze crust has strengthened the snow pack below 2500’ and has been providing spring-like surface conditions below this elevation. 

Snow may be scarce below 1500', but a good time can still be found in the the upper elevations.  


Mountain Weather

Yesterday cloudy skies slowly broke in the morning and by mid-day it was mostly sunny. Temperatures reached the mid 30’s F during the heat of the day, just enough to cause some melting in the 1-2” of new surface snow on sun exposed aspects. Along ridgetops winds were light (5-15mph) mostly from the East.

Overnight temps dipped into the high 20’s F along ridgetops, but at sea level temperatures remained above freezing. There was light rain overnight with rain/snow line around 2000’, up to a few inches of new snow above 2000’. Winds were variable in Turnagain Pass, with Sunburst experiencing a Southerly direction 10-20mph, and Seattle with light Northeasterly winds 5-10mph. 

Tonight another wave of precipitation is expected to move through Southcentral Alaska bringing up to a few inches of snow to upper elevations. Rain/snow line will be around 1000’, with temperatures cooling off late Saturday afternoon as precipitation backs off. Southeast winds are expected to be 20-30mph. 

 

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 35  .1  40 
Summit Lake (1400') 35  .1 
Alyeska Mid (1700') 35  .14  24 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 28  Var.  12  27 
Seattle Ridge(2400') 29  NE  11   15

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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