Avalanche: Turnagain

Location: Eddies

Date:
Observer:
Route & General Observations

Standard uptrack; two runs, one following the uptrack and the second on the main western face

Avalanche Details
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Trigger UnknownAvalanche Type Soft Slab
Aspect South SouthwestElevation 2500ft
Slope Angle 38degCrown Depth 5in
Width 70ftVertical Run 25ft
Avalanche Details

Four D1 slides - with crown depths from 2-8" - ran down the steep SW aspect below the cornice that is just adjacent to the normal up-track, near 2500'. These ranged from 25-75' wide, running 15-25'. See photo below. They may have been remote triggered; we experienced a collapse just above one of them, and tracks went just below each slide.

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)?No
Observer Comments

One collapse on a recently deposited windslab at the top of the route (2500'). Hand pit at this location revealed a 6" slab, failing on an interface within the new snow that has fallen since Thursday.

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

Light snow, averaging ~1cm/hour. East/NE winds light gusting moderate at alderline, increasing to short periods of moderate gusting strong (25+ mph) at the top of the route. Temps near freezing at the parking lot, high 20s up top.

Snow surface

2" of snow over a melt freeze crust at the parking lot this morning; the crust dissipates at 1000'. 1" of new snow during our 4 hour tour at the parking lot.
At treeline in sheltered areas, 6" of snow from the past few days sat over soft facets.
Saltating and occasional blowing snow along much of the route above alderline, but slab formation seemed to be limited to 2000' and higher.

Snowpack

Hand pits where recent wind slabs (up to 6" thick) could be found were failing after a few taps with low energy, on a thick interface within the new snow that has fallen since Thursday. This differed from yesterday on Seattle ridge, where they'd occasionally fail on the facets and surface hoar buried last week.

Numerous rocky patches are still present at the top of the western aspect... lots of previous wind!

Photos & Video
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