Observation: NWAC Forecaster

All Observations

Basic Information

Observation Date:

January 3, 2022

Submitted:

January 3, 2022

Observer:

NWAC Forecaster - Irene Henninger & Lee Lazarra

Zone or Region:

West North

Location:

Heather Meadows (N and W 4200- 4800ft)

Recent Avalanches?

Yes

Cracking?

Widespread

Collapsing?

None Experienced

It was stormy and wind was constantly shifting snow around. We found many small test slopes to check for instabilities.

Shooting cracks occurred easily in this skin track test, where I stepped a few feet uphill of my partner's tracks.

Small avalanche in the January 3, 2021 storm snow on a small road cut bank leading up to Heather Meadows.

Advanced Information

Cloud Cover:

Obscured

Temperature:

24°F

Wind:

Moderate , S

New/Recent Snowfall:

Heather Meadows Telemetry reported 3" Water/~30" of snow by midday since start of storm (24 hours ago)

Difficult to determine previous snowfall amount and current rate due to strong winds and redistribution. Currently about S4, extensive drifting and most surfaces were low density and had a high possibility of more transport (Ski pen was approx 20cm).

Avalanche Observation Comments:

Two avalanches were seen on small road cuts just below Heather Meadows- likely occurring when the bottom was undercut with a plow. Failure depths were about 20cm.

Was unable to cause avalanches on test slopes due to small, supported nature (cracking occurred), but was able to trigger one D1.5 avalanche on a larger, unsupported slope with a hard push from the top. The cracking and avalanches occurred in wind-loaded areas.

Poor visibility made it difficult to see if any natural avalanches had occurred.

An obvious weakness was present in a storm layer change about 20cm down from the surface. This was surprisingly consistent considering the extensive wind transport past and current. Cracking easily occurred on wind lips and on skin track tests (see photo). Several hand shears revealed the same weakness, several times failing on isolation.

A pit on Austin Pass yielded a 270cm snowpack. The only stability test result yielded the same failures as what we'd been seeing in the surface layers while traveling- CT11RP 20cm down. The Solstice Crust was 120cm down from the surface, and was a thin (1cm) P+ crust, which we could not get a result on in a deep tap test. ECTX.

Problem	Location	Distribution	Sensitivity	Size	Comments
Wind Slab	N E S W	Isolated Specific Widespread	Unreactive Stubborn Reactive Touchy	D1 D1.5 D2 D2.5 D3 D3.5 D4 D4.5 D5	Layer Depth/Date: 20cm Comments: Travel was limited but suspect similarities at all other aspects and elevations. Failures occurred or were suspect in all areas we traveled on steep, unsupported wind-loaded slopes. Appears to be rapidly strengthening.

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