Avalanche Advisory

Turnagain Area Avalanche Advisory
Friday, February 5th 2016 7:00 am by Aleph Johnston-Bloom
ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.
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The Bottom Line

The avalanche hazard is HIGH above 1000'. Large natural and human triggered avalanches are likely today.  Over 3" of water (+3' of snow above 1500') has fallen since Tuesday night and is resting on weak snow over a crust. This set-up combined with strong winds and warm temperatures have created very dangerous conditions in the backcountry. Additional snow, rain and wind will continue to stress the snowpack. Travel in or near avalanche terrain is NOT recommended today. 

Below Treeline ( -1000') a MODERATE danger exists where an avalanche in steep channeled terrain could run into this elevation band.

 Show the Complete North American Avalanche Danger Scale
4 High Alpine / Above 2,500' Travel Advice: Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.
4 High Treeline / 1,000'-2,500' Travel Advice: Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.
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

State of Alaska Department of Transportation & Public Facilities Avalanche Closure Notification: There will be intermittent traffic delays today on the Seward Highway for avalanche hazard reduction work between Girdwood and Portage near mileposts 89 to 82.

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Avalanche Problem 1

Storm Slabs: Today is day 3 of a warm and wet storm that has dumped 3" of water (2-4' of new snow in the upper elevations) in the advisory area. This has fallen on old weak (faceted) snow resting on a rain crust. The storm snow was not bonding well to this yesterday and was reactive in tests, whumpfing, cracking and became increasingly 'slabby' throughout the day. Because the crust/facet combo extends from 1000' to approximately 3000' avalanches could be very large and connected. The storm last week stabilized quickly. It is important to recognize the character of this set-up is very different and could elevate the hazard through the weekend. Travel in avalanche terrain is not recommended today. 

Wind SlabsStormy conditions continue to make wind slabs a concern for the upper elevations. Sustained 30-40 mph ENE winds, gusting in the 70s yesterday, have made triggering a wind slab +3’ thick likely on wind loaded and cross-loaded features. Below 3000’ these wind slabs are sitting on the old snow/crust combo and may propagate further than expected. 

Cornices: Cornices will be unstable today and may release naturally. These features have been tender over the last week and now have the added stress of high winds and new snow. These backcountry bombs can easily trigger a slab below and are another reason to avoid travel in avalanche terrain today.  

Avalanche Problem 2

Wet Snow: Wet snow is sitting on a slick crust in the mid elevation band. Rain to 1600’ will be lubricating this poor interface making wet avalanches possible in the mid elevation band. This hazard will be especially dangerous under big open slopes and in terrain traps like gullies or abrupt transitions where an avalanche from above could have high consequences. Natural activity is possible in steep channeled terrain and will likely entrain wet snow. Areas like lower Seattle Ridge should be avoided. 

Additional Concern

Warm temperatures, rain and wet snow continue to add weight and stress to glide cracks throughout Turnagain Pass. These unpredictable hazards are widespread in steep terrain between 1000’ to 2500’ and can release without warning. Today’s limited visibility will make it challenging to identify existing glides, and is an added reason to avoid being in the mountains today. 


Mountain Weather

Yesterday was a storm day. Rain fell up to 1500' and the advisory area recieved another 1.5" of moisture. Snowfall was up to an 1"/hr for much of the day with over 1' of new snow falling in the last 24 hrs. Since Tuesday evening 3" of water and +3' of snow have fallen. Winds were from the ENE blowing 30-40 mph gusting into the 70s. Temperatures were in the 30Fs at 1000' and the mid-20Fs at 3000'. 

Rain and snow showers are forecasted to continue today with an addtional 0-4'' of snow and rain up to 1600'. Winds will be Easterly 15-25 mph and temperatures will be in the 30s. 

Showers continue this evening tappering off overnight with a short break before the next Low impacts the area Sunday. 


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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 31   10 1.7  114 
Summit Lake (1400') 32  3  .3  31
Alyeska Mid (1700') 32  9.5  1.3  84


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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 24   ENE  34 76 
Seattle Ridge(2400') 26  n/a n/a  n/a 

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: Oct 05, 2019 )

Glacier District
Johnson Pass: ClosedClosed
Placer River: ClosedClosed
Skookum Drainage: ClosedClosed
Turnagain Pass: ClosedClosed
Twentymile: ClosedClosed
Seward District
Carter Lake: ClosedClosed
Lost Lake Trail: ClosedClosed
Primrose Trail: ClosedClosed
Resurrection Pass Trail: ClosedClosed. Will be open for the 2019/20 season pending adequate snow cover.
Snug Harbor: ClosedClosed
South Fork Snow River Corridor: ClosedClosed
Summit Lake: ClosedClosed

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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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