Avalanche Advisory

Turnagain Area Avalanche Advisory
Monday, February 5th 2018 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

A generally LOW avalanche danger exists in the mountains surrounding Turnagain Pass. Although triggering an avalanche large enough to bury a person is unlikely, isolated slabs 1-2’ deep can still be found in steep and/or wind loaded areas. LOW danger does not mean No Danger. Additionally, watch for cornices along ridgelines and sluffs in steep terrain. 

*Periphery zones, such as Girdwood to Portage Valley, and Johnson Pass to Summit Lake more caution is advised where a slab could be larger and more connected.

Check out the Summit Lake Summary HERE. 

 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.
Special Announcement

For all the Hatcher Pass users out there - Hatcher Pass Avalanche Center is having their annual fundraiser this Saturday night, Feb 10th at the Palmer Moose Lodge!! HPAC is a growing avalanche center for a high use zone with a high number of avalanche accidents in Alaska, they need your support! Click HERE for details.

Avalanche Problem 1

Persistent Slabs

Almost Certain
Very Likely


Very Large


Among the thousands of snowmachine, skier and snowboard tracks around Turnagain Pass, don't forget that a slab avalanche could still be triggered in isolated areas. These areas are more pronounced in the periphery of the forecast zone, such as South toward Johnson Pass and Summit Lake, as well as toward Portage and Girdwood Valleys. It is the higher elevation slopes that have seen prior wind loading, or have a very thin overall snowpack that are the most suspect. Keep this in mind, especially if you find yourself pushing out into terrain not yet traveled this year. 

Image on left shows Cornbiscuit near Turnagain Pass with many tracks on it without incident next to the right image of a slab triggered on Saturday in the Twin Peaks area. The Twin Peaks avalanche is on the Southern edge of the forecast zone. (Photos: left, Liz Repetto and right, Andy DuComb)



We are in a 'normal caution' regime at Turnagain Pass and triggering an avalanche is on the unlikely side. However, there is still snow out there that can slide, but it's confined to isolated areas mentioned above. Below are the avalanche issues to be aware of:

Persistent Slabs:  A layer of buried surface hoar exists roughly 1-2' deep and has been responsible for the scattered avalanche activity over the past week and a half of sunny weather. Most areas, especially in the heart of Turnagain Pass, harbor very loose snow over the buried surface hoar and only sluffs are being seen (no slab). It is the areas where the top foot or two of snow is stiffer from wind affect/loading that we need to watch out for. Also, areas where the buried surface hoar is simply deeper due to higher snowfall amounts from our last storm on January 26th, such as in the Portage Valley zone. If choosing to push into the steep and committing terrain, watch for:

-  Areas winds have affected the snow, stiffer snow over softer snow
-  Shooting cracks
-  Hand pits to see if you can find the buried surface hoar and get a block to slide off
-  Before committing to steep terrain, 
identify terrain traps like gullies, cliffs or rocks below to consider the consequences if even a small slab is released

*Deep Persistent Slab:  Weak snow can still be found near the ground at the upper most elevations in our forecast area, 3,000' - 5,000'. Although triggering a Deep Persistent Slab is very unlikely, it is worth keeping in mind that poor structure does exist at the high elevations. 

Loose Snow 'sluffs':  In most places the snow is very loose and ’sluffs’ easily on the steeper slopes. Watch your ‘sluff’ and be aware of the consequences below you.

Cornices:  Cornices are unpredictable and can break further back along a ridge than expected. Give these features plenty of space. 

Mountain Weather

Sunny skies and light variable winds were over the region yesterday. Temperatures climbed into the mid 20'sF in the Alpine and remain there this morning. Valley bottoms warmed to the teens in many places yesterday, and have dropped back to the minus single digits this morning.

Today, skies will start clear before clouds begin to stream in mid-day, or perhaps this afternoon as a low-pressure system is headed our way for tonight/tomorrow. Ridgetop winds are expected to rise to the 5-15mph range from the East. Snowfall, up to a couple inches, is expected overnight. Temperatures will remain cold in valley bottoms today and in the 20'sF at the mid and upper elevations.

Tomorrow, Tuesday, snowfall should continue and forecast models are showing a total of 3-6" by Tuesday evening. Temperatures will warm to around 30F at 1,000', but should stay cold enough for snow to sea level. Ridgetop winds are expected to increase early Tuesday to the 25-30mph range from the East.


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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 18  62 
Summit Lake (1400') 18 
Alyeska Mid (1700') 17  50 


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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 23 
Seattle Ridge(2400') 24   4

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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