Avalanche: Hatcher Pass

Location: IM to Marmot test slope to NW Microdot (Airbag Alley) to Gold Chord

Date:

January 2, 2020 9:00pm

Observer:

Barker Workman Forecaster

Route & General Observations

Toured from IM Lot up to Marmot test slope to Microdot to Gold Chord. Observed several 1-3 day old natural slabs on leeward aspects at mid and upper elevation. Observed one D1.5 human triggered slab in Rae Wallace. No cracking or collapsing observed today.

Avalanche Details

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Trigger	Skier	Remote Trigger	Unknown
Avalanche Type	Soft Slab	Aspect	North
Elevation	3800ft	Slope Angle	unknown
Crown Depth	unknown	Width	unknown
Vertical Run	unknown

Avalanche Details

Observed human triggered soft slab in Rae Wallace from below. Rider human triggered the avalanche and was able to ski out. The slab most likely failed on buried NSF's (near surface facets) in the new snow/old snow interface. Rider was not caught or carried.

Red Flags

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Obvious signs of instability

Recent Avalanches?	Yes
Collapsing (Whumphing)?	No
Cracking (Shooting cracks)?	No

Observer Comments

Observed at least a dozen natural slabs that likely occurred 1-3 days ago after the big wind event. All slabs were observed on leeward aspects, W to N, at mid and upper elevation on slopes above 35 deg. Slabs were mostly small in size and ranged from D1-D2. One D1.5 human triggered soft slab was observed in Rae Wallace today.

Dozens of recent natural small dry loose sluffs were observed on all aspects at mid and upper elevation in steep terrain today. Human triggered dry loose sluffs were also observed today.

Weather & Snow Characteristics

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

Weather

Clear skies, light winds, and cold temps today.
0 degF at 4500' at 1100, winds E 8 mph
2 degF at 4500' at 1300, winds E 6 mph
High of 2.5 deg F today at 4500'

Up to 12" light density snow since Sunday

Snow surface

Up to 12" new snow since Sunday.

Snowpack

See documented Pit 1 in pictures

Pit 2: Microdot, Top of Airbag Alley, NW, 4200', HS 180cm
ECTP1 d20cm on decomposing fragmented
ECTN5 d30cm wind slab / near surface facets

Pit 3: Microdot, Airbag Alley, NW, 4100'
Two slabs upside down in upper snowpack, some propagation, high friction
ECTX
CT12RP d55cm 1F slab / 4F Decomposing fragmented
CT14RP d70cm 1F / 4F Near surface facets

Photos & Video

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