Avalanche: Douglas Island

Location: Lower Troy Bowl, Douglas Island

Date:
Observer:
Mike Janes
Route & General Observations

Two natural avalanches observed on Troy/False Troy. Heavy new snow (wind affected) at surface. Cold front bringing showers and off and on gusty winds.
Video is from lower Troy bowl and is testing the weaker freezing rain crust/facet snowpack structure.

Avalanche Details
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Trigger UnknownAvalanche Type Soft Slab
Aspect SouthwestElevation 2700ft
Slope AngleunknownCrown Depth 10in
Width 200ftVertical Run 300ft
Avalanche Details

Natural slide off False Troy/Troy Saddle just to the north of the saddle (see photo). Crown was filled in but could have been over 12" in places. I am guessing this face was scoured of the old freezing rain crust/facets so it seems probable this released on the new snow/ new freezing rain crust interface but this was not verified.
Also noted a natural slide from below rocks/cliffs on the West aspect of Troy from around 2400'(see photo)

Red Flags
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Obvious signs of instability
Recent Avalanches?Yes
Collapsing (Whumphing)?No
Cracking (Shooting cracks)?Yes
Observer Comments

Recent wind transport

Weather & Snow Characteristics
Please provide details to help us determine the weather and snowpack during the time this observation took place.
Snow surface

Firm wind affected new snow

Snowpack

3x different scenarios:
-Previously wind blasted icy layer with thin layer of new snow/freezing rain crust weak layer with all the new snow on top
-Old freezing rain crust with facets underneath, with the new snow/new freezing rain crust weak layer and new snow on top of that
-The above setup but with a wind slab on top of the old freezing rain crust
Testing the top layers, no propagation, but testing the middle setup, ECTP11 sudden collapse

Photos & Video
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Troy West aspect cliff band natural avalanche  

False Troy natural avalanche  

Weaker facet/freezing rain crust structure with new freezing rain crust and new snow on top.  

Location