Avalanche Advisory

Turnagain Area Avalanche Advisory
Sunday, January 28th 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

There is a MODERATE avalanche danger at all elevations for wind slab and soft storm slab avalanches between 1-2' thick. Thursday's new snow is sitting on buried surface hoar and in areas the new snow is cohesive and stiffer (due to wind or settlement) triggering slabs will again be possible. Additionally, loose snow avalanches (sluffs) will be likely on steep slopes.  At high elevations, above 3,000', there is still a chance someone could trigger a deep persistent slab avalanche.

 Show the Complete North American Avalanche Danger Scale
2 Moderate Alpine / Above 2,500' Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
2 Moderate Treeline / 1,000'-2,500' Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
2 Moderate Below Treeline / Below 1,000' Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
Special Announcement

A quick shout out to all the folks that joined us for our Beacon Practice clinic yesterday at Turnagain Pass and to the Anchorage Snowmobile Club for hosting the event!! 

Avalanche Problem 1

Persistent Slabs

Almost Certain
Very Likely


Very Large


A glorious sunny Saturday coupled with 20" of new low-density snow two days prior and it was no surprise many folks were out enjoying themselves in the mountains yesterday. With many people on the slopes it is not big surprise many there were 8 reported avalanches at Turnagain Pass and one in the Girdwood Valley. As far as we know, no one was caught in any of these and many were remotely triggered. They ranged in size from very small to just large enough to bury a person and did not propagate very wide. They were all soft slabs 1-2.5' thick, less than 100' wide and composed of Thursday's new snow. Please see the list of observations sent into us HERE as well as highlighted photos below - a huge thanks to all the folks taking the time to send us their photos and reports! 

The new snow is sitting on a layer of buried surface hoar that is inhibiting bonding to the old snow surface. This is creating a new persistent slab avalanche problem for our mountains that could linger for some time. The reason these slabs have not been propagating into larger avalanches is the slab is still very soft and generally non-cohesive. The areas the slab is cohesive is where triggering is possible, such as where winds have loaded/stiffened the snow, where the slab has settled and become cohesive on it's own and it's that time of year where the sun can create a slab by warming steep South aspects. Hence, if you are headed out today, and this week, keep these points in mind:

- Are the winds picking up enough to transport snow? This will be a big question moving forward for slab development!
- Quick hand pits are great ways to assess changes in the new snow character
- Watch for cracking and whumpfing - this was prevalent yesterday
- These avalanches may seem small now, but could start to propagate wider with passing time and/or fresh wind loading 

*Remember your safe travel protocol - expose one person at time, watch your partners, have escape routes planned

Fourth skier on slope triggered this slab avalanche on Max's Mountain  pictured below, SW face at 3,000'. 


Two skier remote triggerd slabs on the upper SW face of Eddies Ridge  (Photo: Joe Engel)


 Snowmachine triggered wind slabs in Main Bowl (1st Bowl) of Seattle Ck drainage near the Widowmaker slide path (Photo: Bryan Pfaender)


Skier triggered slab with a ski cut on Tincan Proper, 1-2.5' thick and 30' wide (Photo: Meg Smith)


Small wind slab human triggered in Hippy Bowl on Tincan Ridge, westerly facing rollover (Photo: Heather Thamm)


Avalanche Problem 2

Dry Loose

Almost Certain
Very Likely


Very Large


Loose snow avalanches ‘sluffing’ is possible on steep terrain features protected from wind. Small slabs may entrain loose snow below and could run faster and farther than expected. 

Additional Concern

Deep Persistent Slabs

Triggering a deep slab is becoming difficult, but is still possible above 3000' where a hard slab is sitting on a variety of weak layers in the mid pack and near the ground. The most likely trigger spots are in thin areas in the snow cover, often near rocks, or where the slope rolls over. The Southern end of Turnagain Pass to Johnson Pass is more suspect due to a thinner snowpack. Remember, this is a 'low probability, high consequence' situation. 

*** There is very little info in the Johnson Pass and Lynx Creek zone. If you're headed to either of these areas and you observe any signs of instability: recent avalanches, shooting cracks, or whumpfing please send us an observations HERE

Mountain Weather

Sunny skies and light variable winds were over the area yesterday. Temperatures were in the mid 20's at all elevations. A thick valley fog below 1,500' developed late in the day. Overnight skies have remained mostly clear above the valley fog.

For today, Sunday, sunny skies are expected again with winds shifting Northerly and slightly increasing to 5-10 and possibly 15mph in places. These winds will bring in a cooler air mass so expect temperatures to be trending to the chilly side, 5-10F along ridgetops. Overnight tonight, the wind could increase up to 20-25mph from the North.

This coming week, clear skies and cool temperatures are on tap. The winds will be the weather parameter to keep an eye on and we'll be watching this. Stay tuned.


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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 24  70 
Summit Lake (1400') 20 
Alyeska Mid (1700') 18  54 


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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 17  NE 
Seattle Ridge(2400') 20  SE  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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