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Observation: Turnagain

Location: Twin Peaks (Twin Tips)

Date:
Observer:
Route & General Observations

Standard skin track up the east facing shoulder to a high point of 2700′. Looking for the distribution and reactivity of the 1/21 Buried Surface Hoar (MLK Jr BSH) layer within the snowpack. Also looking for previous buried surface hoar layers, and the changing surface conditions with the increased winds.

Red Flags
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Observer Comments

Winds began to pick up around 1300 (1pm). Could see transport off most high peaks.

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

Low 20s F
Light to Moderate Winds - Gusting to 25mph
Few Clouds - moving in around 1pm
No Precip

Snow surface

Road to ~1150' - A thin eggshell moisture crust decreasing to 1"of soft snow on top of a supported surface.
~1150'- Loss of the supportable surface crust.
~1300' - 2" of soft snow on top of a thin crust sandwich with 1mm facets in between two crusts.
~1500' - Loss of crust sandwich, 8" of soft snow on top of a 6" crust interface.

Snowpack

The MLK Jr Day (1/21) BSH layer was found in test pits dug between 2300' and 2700'. In both of these pits we found a mixture of BSH as well as faceting occurring near these layers. All pit locations presented propagation propensity on or involved with the MLK Jr Day BSH.

Twin Peak Test Pit 1- 2250' - HS: 140cm - E Aspect - 28*
CT19 / CT26 failed 40cm down on MLK layers (MF crust /BSH/.5mm facets/MF)
ECTP13 /ECTP23 failed 40cm down on MLK layers (MF crust /BSH/.5mm facets/MF)

Twin Peak Test Pit 2 - 2300' - HS: 130 - E Aspect - 31*
STE failed 25cm down on MF/BSH - large obvious upright BSH (5-7mm) within facets (.5mm)
CT6 failed 25cm down on MF/BSH
ECTP9 / ECTN12 failed 25cm down on MF/BSH

Twin Peak Test Pit 3 - 2700' - HS:160 - E Aspect
Tests failing directly below the BSH (3-4mm) under thin crust within facet layer (.5mm)
CT17 failed 25cm down on thin crust/facet layer
ECTP25 / ECTN17 failed 25cm down on thin crust/facet layer

Photos & Video
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