Observation Date: 01/13/2019

Route/Location:
Area between Ridgeline and Stateline Yurts outside of Lost Trail Ski Area 1/11-1/13.

Weather:
Inversion was set up strong with valley fog below ~7,600 feet and warmer temps above the clouds.

Wind:
light wind throughout our trip.

New Snow: No New Snow

Avalanche Activity:
Small point releases observed on solar aspects with exposed rocks during warm periods with lots of solar impact.

We experienced multiple whoomps on N-W-S aspects with shallower snowpacks.

Other Comments:
This area is currently defined by 2 different snowpacks. We found a shallower and weaker snowpack on S-W aspects, and a deeper, stronger, and more cohesive snowpack on E-N aspects.

We dug several pits, toured, and skied multiple aspects all 3 days.

On S-W aspects we generally found shallow snow depths: 55-75cm. We found multiple layers of concern including: buried surface hoar, facets, and depth hoar. We saw propagation with easy force, and propagation on column isolation in some pits. These pits showed low friction and very poor structure. Some pit results: (7.5-8k ft S-W aspects, 28-35′ slopes): ECTP 8, ECTC, PSTC, & PST 10/100.

On E-N aspects we found snow depths averaging 120cm. We had a harder time locating buried SH on these aspects, found greater stability, no propagation, higher friction, and generally, a more cohesive snowpack structure.

Non solar aspects, shaded areas, and areas below the inversion harbored large SH on the surface. Some SH has been heavily rimed.

Observer: BURKET KNIVETON