Avalanche: Turnagain

Location: Eddies

Route & General Observations

I saw a recent hard slab avalanche that propagated very wide and failed deep in the snowpack.

Avalanche Details
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Trigger UnknownRemote Trigger Unknown
Avalanche Type Hard SlabAspect West Southwest
Elevation 2000ftSlope Angle 26deg
Crown Depth 24inWidth 1000ft
Vertical Run 300ft  
Avalanche Details

This avalanche failed on a layer of surface hoar that was buried during the 11/20-11/21 storm. It occurred on a wind-loaded slope and propagated about 1000' wide. The crack propagated through wide portions of the slope and adjacent slopes that weren't steep enough to slide. It was surprising how low the slope angle was at the crown; I measured a slope angle as low as 26 degrees! There were many pockets in the track where the avalanche stepped down to the facets at the ground. It looks like there is an observation from 11/20 describing a skier-triggered a soft slab on the same slope just before the storm.

Red Flags
Red flags are simple visual clues that are a sign of potential avalanche danger. Please record any sign of red flags below.
Obvious signs of instability
Recent Avalanches?Yes
Collapsing (Whumphing)?Yes
Cracking (Shooting cracks)?Yes
Observer Comments

All of the signs were there, although collapses were a little less frequent today than they were yesterday at Tincan.

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

There was about a foot and a half of snow at 2000'. Winds were calm, and air temp was 23 F.

Snow surface

Plenty of fresh snow. Great (albeit a little spooky) riding conditions!

Photos & Video
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