Avalanche: Turnagain

Location: Upper Lyon Creek

Date:
Observer:
Avalanche Details
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Trigger CorniceAvalanche Type0
Aspect WestElevation 4100ft
Slope AngleunknownCrown Depthunknown
WidthunknownVertical Rununknown
Avalanche Details

Nice cornice avalanche in Upper Lyon Creek. Debris pile was >10' deep, with one chunk about the size of a school bus.

Red Flags
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Observer Comments

No signs of any post-storm avalanches except for the cornice triggered slide in the picture.

Weather & Snow Characteristics
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Snow surface

great snow above 2000'.

Snowpack

We dug a pit on a ~33 degree slope at 2800', west aspect. 4.3 m total snow depth. CT failed at 27, down 70 cm (28"), Q2 (clean and planar, not fast). Appeared to be the Jan 27 interface (i.e. the drier snow before it warmed up). No failure on that layer with an extended column test.
In this pit the storm snow was comprised of a 35 cm 1F slab, topped by a thin (~2 mm?) raincrust, and then 35 cm of nice F. 5 mm hoar on surface. No clean failures on the raincrust, even in shear.

Photos & Video
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