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Observation: Summit

Location: Tenderfoot

Date:
Observer:
Route & General Observations

Standard up-track up Tenderfoot to a high point of 3400′. Looking for the distribution and reactivity of the 1/21 BSH (MLK Jr BSH) in the upper elevations of Summit.

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)?No
Cracking (Shooting cracks)?No
Observer Comments

Cornice fall of SW Aspect of Butch above 3500'
Natural D1.5-2 Slab Avalanche SW Aspect of Butch above 3000'

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

Mid 20s
Clear-Few sky above 2k
Broken Valley fog 2-2.5k throughout the day
No Precip
Calm-Light NW Winds

Snow surface

Parking lot ~ 1700' - Eggshell Rain Crust of thin snowpack 10"
~1700' - Loss of Eggshell crust, new precip. 4-10" increasing as elevation increased
~1800' - New Surface Hoar formation 5-7mm is present
~2700' - Obvious wind effect/transport appears. Variable scoured surface with 1-5" new precip on it depending on wind effect. Locations with low wind effect still had SH formation.

Snowpack

The MLK Jr Day (1/21) BSH layer was still found wide spread at multiple elevation bands. We saw it in multiple lower-mid elevation (1500-2500') hand pits and in test pits on different wind effected aspects within upper elevation bands (above 3000').

Beginning at 1800' - we found a 1" melt freeze / near surface facet crust interface (NSF/MF/DF .5mm) above the MLK Jr BSH buried approx 12" down and shear with moderate force in a planar fashion. The hand shears were failing on the MF/NSF interface, not within the BSH. This was the same type of interface we were finding at Tincan earlier in the week.
2400'- we found the MF interface (NSH/MF/DF .5mm) layer was decomposing to more of a thin eggshell above the MLK Jr BSH buried approx 16" down and shear with moderate force in a planar fashion.
2700'- we found the MLK Jr. BSH buried approx 10" down and shearing with moderate force in a planar fashion - on the MLK Jr. Layer.
3000'-We explored a very wind scoured SW aspect with a shallow snowpack (65cm) with approx 6" new precip on 20" of decomposing/faceting pencil hard melt freeze layers with large (8-10mm) BSH throughout as well. This all sat on top of a weak layer 10-12mm Depth Hoar. This pit gave zero results in the stability tests. (CTN ECTX).
3400'-We explored a wind loaded SW aspect with deeper snowpack (210cm). In this we found the MLK Jr BSH (4-6mm) buried 12" down on top of a 12" knife hard wind layer. We also found the 1/11 BSH (2-5mm) directly below the knife hard wind layer. This showed propagation propensity on the MLK Jr BSH (ECTP27).

Upper Tenderfoot Pit - 3400' - SW - HS:210
CT15 down 30cm
ECTN15 down 20cm new old interface
ECTP27 down 30cm on 4-6mm MLK Jr BSH

Photos & Video
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