Observation: Turnagain

Location: Tincan, Above Treeline

Date:
Observer:
Route & General Observations

10:00-4:00
We took the standard approach to our high point of 3,300’, and conducted instability tests in two locations, treeline and above treeline, with results showing good stability overall and great skiing.

Visibility above 3,500’ was obscured for most of the day, and though we did not observe wind plumes, weather rapidly deteriorated after 14:00 with increasing snowfall rate and moderate SE winds.

Red Flags
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Observer Comments

No cracking, collapsing
Test slopes produced small releases of 1-4" of low density, fresh snow over wind hardened surfaces on convexities above 2,500'.
Winds increased abruptly to moderate by 14:00 and we observed active wind loading on exposed terrain.

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

Overcast trending to obscured above 2,500’ with no valley fog.
Light trending to moderate winds shifting from NE to SE in the AM.
Light increasing to moderate snowfall by 14:00.
19°F at 3,100’ (13:00)
No riming observed

Snow surface

At treeline and above, 5-7” of low density accumulation from the past few days sits over varied wind stiffened layers ranging from hard, echoing wind slabs in exposed terrain, to soft snow from the last storm cycle in sheltered terrain.
At 1,500’ , HS 175cm, the 12.5 rain crust was present 55cm below surface, with the 12.1 melt-freeze crust was present 70cm below.
At 2,400’, HS 155cm, the 12.1 rain crust was present 45cm below surface.

Snowpack

In general, my focus was assess the reactivity of the upper snowpack, and get eyes on the basal facets. Tests as both locations showed moderate strength and no propagation propensity with great stability.
Our first pit at 2,400’,W aspect, 19° slope, HS 155cm, I received no results on multiple CT tests, and could see the 12.1 Melt-freeze crust sandwiching a facet layer within.
Our second pit, see Snowpilot profile, continued to show great stability with hard results on CT’s, along with no results on Deep Tap Test and an ECT.
My layer of concern are still the basal facets, but it's continuing to show a strong bond with the ground surface below in test pits.
(See pictures below)

Photos & Video
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