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Observation: Turnagain

Location: Taylor Pass

Date:
Observer:
Route & General Observations

Skinned up Taylor Pass and descended the same route.

Red Flags
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Observer Comments

None observed, until we returned to Girdwood where there was a remote triggered avalanche on Raggedtop on a SE aspect.

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

Clear and sunny
Cool light breeze
Temps 20F's, but could feel radiation through clothing.

Snow surface

Hard and variable. 1" breakable m/f crust to 2000' on all aspects elevations. There is loose (faceting) snow below this crust. Above this the surfaces are either scoured to old hard, anti-tracks, or breakable wind hardened snow. There a few patches of soft snow, but slim pickings. There's a supportable sun crust on steep Southerly and SE aspects, but could feel it softening on steep features when we skied out at 5:30pm. Slopes less than 35 degrees remained cold and dry on Solar aspects.

Snowpack

We probed around at 3100' just below Taylor Pass and total height of snow varied from 120cm to 220cm. We chose to dig two pits one in a shallow area and one in a deeper area to look for the Jan.21 buried surface hoar and facets. We were also curious about the spatial variability the slab thickness on this layer.

Pit 1: 3100', W aspect, 24* slope, HS=205cm - The January 21 buried surface hoar and facet layer was 85cm (34") below the surface and failed with moderate force in Compression Tests. We did not have failure on Extended Column Tests, but did have propagation with moderate force on a Deep Tap Test. The thickness of the Jan.21 BSH/facets was 2cm thick and was 4F hard with Pencil hard snow above and below. The surface hoar was old and decomposing, but the facets were still loose and 1mm in size. Results: CT15, CT16, DT15, ECTXx2

Pit 2: 3100', W aspect, 15* slope, HS=120cm - The January 21 buried surface hoar/facets were 30cm (12") below the surface and failed on isolation in a compression test (CTV.) We had propagation with moderate force on one Extended Column Test and no propagation in two others. The slab crumbled under shovel. See video. (ECTP13, ECTN15, ECTN16) There bottom 60cm of the pit were a mix of stout pencil hard crusts with some faceting between crusts. We also found depth hoar on the ground or just above a thin ice crust on the ground. These basal facets failed with strong force in a compression test (CT25.) This layer was loose in some places especially were it was sitting on the thin ice crust.

Photos & Video
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