Avalanche Advisory

Turnagain Area Avalanche Advisory
Friday, March 10th 2017 7:00 am by Wendy Wagner
ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.
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The Bottom Line

LOW avalanche danger remains in the backcountry at all elevations. Although triggering an avalanche is unlikely, it is not impossible. Today's main question is daytime warming. Watch for East-through-South-through-West-facing slopes to heat up enough to initiate rollerballs and possibly some shallow wet loose avalanches. Other things to watch for are old hard wind slabs in steep rocky terrain, dry sluffs on steep slopes with soft snow and cornice falls loosening with the warmth. Glide cracks continue to open - limiting exposure under these is recommended.

Remember that good travel habits remain important, even during 'green light conditions'. This includes exposing only one person at a time on a slope, watching your partners closely and having an escape route planned in case the snow moves. 

Summit Lake, South of Johnson Pass and North (in parts of the Girdwood Valley):  A reminder that the snowpack remains thin with a poor structure. The chance for tiggering an avalanche that breaks in the old weak layers is unlikely but not nonexistent. 

 Show the Complete North American Avalanche Danger Scale
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.
1 Low Below Treeline / Below 1,000' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
Avalanche Problem 1

Sunshine and warmer temperatures are on tap. After 11 days of clear skies and cold single digit temperatures, today is expected to be the warmest day since the Northwest winds ripped though during the end of February. Winds are slated to be calm to light from the South and should let the sun do its thing on East, South and West aspects - meaning warm things up to the 20'sF or higher. Keep a close eye on any warming taking place on the snow surface. Soft snow still sits on many slopes and roller balls and wet loose avalanches could occur in these areas. Slopes with old sun crusts or wind slabs/crusts will take much more than the warming today to effect. 

Other things to keep in mind if you are headed to the mountains to enjoy these long sunny days:

Glide Avalanches:
Glide cracks continue to slowly open above popular terrain on Seattle Ridge and in other areas of the advisory area. These could release at any time, watch for these cracks and avoid being under them.

Wind Slabs:
Old and hard winds slabs are easy to find but for the most part they are locked into place. Steep rocky areas, where they are not supported from below, will be the most suspect zones for someone to pop one out. 

Loose Snow Avalanches (Sluffs):
Watch your sluff. Dry sluffs on steep slopes are probable and are getting larger by the day. And, as mentioned above, wet loose (or damp) sluffs, both natural and human triggered, may occur.

Cornices may start to loosen with the warming - as always, give these monsters a wide berth from above and limit exposure time traveling underneath.

Persistent Slabs and Deep Slabs:
There are various weak layers in our thin snowpack. Buried surface hoar sits 1-3+' below the surface and faceted snow sits in the mid and base of the pack. These weak layers with varying degrees of strength are in a dormant stage due to plenty of time to adjust with a lack of changing weather. Although this means the layers are not producing avalanches, it doesn't mean an outlier can't occur which could cause a large avalanche breaking deeper in the pack. 


 The most interesting glide crack of the season sits just to the looker's left of the motoroized up track. We are following this one closely to see if and when it will releases. 

A look at Tincan Ridge from the motorized side of the road. Sun crusts are becomming more prevolent, although plenty of soft 'recycled powder' is still to be found.


A quick look at the Turnagain Pass snowpack from the Center Ridge SNOTEL site. Our snowpack is just over half of normal for this time of year.

Mountain Weather

Sunny skies were over the area yesterday (the 11th day in a row for brilliant sunny skies!). Ridgetop winds were light from the North. Temperatures climbed from around 10F to 15F overnight and sit warmer than they have been for 12 days! That said, an inversion is in place this morning with valley bottoms -10F to 0F.

For today, sunshine and calm winds should warm up the lower elevations to the mid 20'sF, ridgetops should warm as well into the 20's. It should be a day for sunscreen instead of balaclavas. Ridgetop winds are expected to be around 5mph from the South.

The weekend looks to be similar with sunny skies and warm afternoon temperatures - the 'nocturnal inversion' will likely keep overnight temperatures cold. There is hit for snow in the long term forecast the middle of next week....cross your fingers!

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 61 
Summit Lake (1400')  0 29 
Alyeska Mid (1700') 13   0  0 57 


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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 13  SW  13 
Seattle Ridge(2400') 13  10 

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 06, 2019 )

Glacier District
Johnson Pass: ClosedClosed as of 4.3.19
Placer River: ClosedClosed as of 3.20.19 due to lack of snow.
Skookum Drainage: ClosedPlacer access closed as of 3.20.19 due to lack of snow.
Turnagain Pass: ClosedClosed as of 5/6. Thanks for a great season all, see you next winter!
Twentymile: ClosedClosed as of 3.20.19 due to lack of snow.
Seward District
Carter Lake: Closed
Lost Lake Trail: ClosedClosed as of 3.22.19 due to lack of snow
Primrose Trail: ClosedClosed as of 4.3.19 due to lack of snow
Resurrection Pass Trail: ClosedClosed for the 2018/19 season. Next season will be open to motorized use.
Snug Harbor: ClosedClose as of 5.1.2019
South Fork Snow River Corridor: ClosedClosed as of 3.20.19 due to lack of snow.
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.

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