Turnagain Pass Avalanche Forecast

Observers yesterday were able to see more of the avalanche activity from the week long storm. There was evidence of a widespread avalanche cycle from Girdwood to the Hope Y.  Some crowns from avalanches earlier in the storm were harder to see and almost covered up by subsequent snowfall and some were distinct and more recent looking. The size of avalanches varied from large destructive slides to smaller pockets.  A few recent cornice falls were also observed. Of note, observers in Summit did not see slab avalanche activity in that area. They did mention a cornice fall in the Incredibowls and a couple of small loose snow avalanches.

Large avalanche on the southwest slope where Skookum meets Placer, 1.13.21. 

Slab on southwest slope of Tincan below the uptrack to Common Bowl almost filled in with snow. 1.13.21

Today east winds are forecast to be elevated throughout most of day, blowing 15-35 mph with gusts into the 40s and 50s. There is plenty of soft snow available for transport and an additional 3-6″ forecast to fall during the day. This is a perfect recipe for wind slabs. Be careful around terrain where wind slabs typically form– near ridgetops, below rollovers, and in cross-loaded gullies. Pay attention to changing surface conditions and the snow becoming stiffer. Because of the active loading natural avalanches will be possible and being aware of what terrain is above you will be key as well. Watch out for cracks shooting out from your snowmachine, skis or board.

Storms slabs: Decent visibility yesterday afternoon allowed for a better inventory of natural avalanche activity from the storm. There was a widespread avalanche cycle across the forecast area with a number of large avalanches with deep crowns. Signs are pointing to the snowpack stabilizing after this storm but there is still a chance of triggering a slab that breaks deeper into the storm snow. This is another reason for careful travel today.

Cornices: Cornices have grown large and are looming over some terrain. Wind-loading today could tip the balance and cause a cornice fall. Limit time spent underneath and give cornices a wide berth along ridgelines as they often break farther back that expected. A cornice fall today could also trigger an avalanche on the slope below.

Wind transport along Tincan ridge, 1.13.21. Look for blowing snow and active loading today.

Wind effect and cross-loading on Seattle Ridge, 1.13.21. This is a good example of terrain that might develop wind slabs today.

Hippy Bowl cornice, 1.13.21. Part of the cornice fell and triggered a small avalanche in the bowl. Cornices may fall today with additional loading and/or be easily triggered if you get too close.

We have been tracking a layer of faceted snow associated with the 12/1 rain crust, which is now buried around 6-8’ deep, and exists at elevations up to around 2500’. We have not been able to confirm if any of the recent large natural avalanches released at this layer but the vast majority appear to be storm snow only. It is unlikely a person could trigger an avalanche on this layer at the depths it is buried from Girdwood through Turnagain Pass.

The snowpack is shallower in Summit Lake and observers are finding varied reactivity with tests on this layer. However, at this point data is trending towards triggering an avalanche breaking on this layer to be unlikely here as well.  It may get a larger load and become more concerning. We will continue to keep tabs on this crust and any facet development in this area south of our forecast zone.