Professional Observation

Basic Information

Observation Date:

December 29, 2021

Submitted:

December 30, 2021

Observer:

WCMAC - Ryan Sorenson

Zone or Region:

Central Bitterroots

Location:

Camas Lake

Recent Avalanches?

Yes

Cracking?

Isolated

Collapsing?

None Experienced

Cracking on small wind-loaded test slopes isolated to directly under skis in the top 4 to 6 inches. Small wind slab triggered mid-slope on steep rollover at 7,400 feet.

We toured in the Camas Lake area, looking at the extent of wind slab formation and if reactive persistent grains exist.
• Snow surfaces became more wind-hardened above 7,400.
• Wind slabs on small wind-loaded test slopes were stubborn to trigger, and minimal cracking was isolated directly under skis.
• Looking across the canyon south and easterly aspects were scored due to stronger funneled winds. North and westerly aspects show signs of wind loading.
• Persistent grains were present near the base of the snowpack and were not reactive in column tests.
• We accidentally triggered a small soft wind slab avalanche on a steep rollover mid-slope at 7,400 feet on a north aspect. This avalanche was harmless in size, but similar slides could become more of an issue with more wind loading, slab hardening, and depth.
• Plenty of snow is available for wind transport.

Advanced Information

Cloud Cover:

Mostly Sunny

Temperature:

10°

Wind:

Light , W

Winds were calm for most of the tour. We experienced a light westerly breeze at 8,000 feet on the ridgeline. Various cloud layers hung below 7,000 feet with clear skies above. It was lightly snowing as we toured through lower elevations.

#	Date	Location	Size	Type	Bed Sfc	Depth	Trigger	Comments	Photo
1	Today	Camas Lake N 7,400	D1	SS	I-New/Old Interface	6 inches	AS-Skier u-Unintentional