Observation: Turnagain

Location: Tincan Common

Date:
Observer:
Route & General Observations

Route:
Tincan Common

Weather:
Few clouds, temps in the high 20’s to low 30’s, light east winds, no precip.

Obvious Signs of Instability:
Recent Avalanches: Remote triggers from 2/17
Collapsing: Yes at 2500′ on SW aspect just above treeline
Shooting Cracks: None from today

Surface Obs:
Parking lot to 1800′: Firm icy conditions, softening later in the day. Carried skis up first two steep
sections of the uptrack.
1800-2200′: Thin melt freeze crust on surface with loose snow below. Variable size surface hoar.
2200-3200′: Decomposing surface crust with loose snow underneath. Good ski quality. Variable size
surface hoar.

Below the Surface:
We dug pits at 2500′ and 3300′ with significant variation in snowpack structure between these
elevations. At 2500′ the slab depth ranged from 40-55 cm. The weak layer of facets ranged from 10-
15 cm thick. The hardness of the weak layer was four finger in the top 2-5cm and fist from there
down. While digging these pits we triggered a collapse from boot packing around the area.

At 3300′ the slab depth was 60-65 cm and the weak layer was much thinner and harder to detect.
This site also lacked the stout melt freeze crust below the facets that makes them easy to pick out at
lower elevations.

Pit Site 1 2500′ SW 24-28* slope:
ECT P 15-28 (10 total tests) Sudden Collapse
PST 35-50/100 End (10 total tests)

Pit Site 2 3300′ SW 25* slope:
ECT P 16-18 (3 Tests)

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