Professional Observation

Basic Information

Observation Date:

November 26, 2022

Submitted:

November 26, 2022

Observer:

WCMAC - Cam Mackenzie

Zone or Region:

Southern Bitterroots

Location:

Lost Trail Backcountry

Recent Avalanches?

None Observed

Cracking?

None Experienced

Collapsing?

None Experienced

Stability Rating:

Fair

Confidence in Rating:

Stability Trend:

Poor snowpack structure overall. North aspects developing depth hoar but bridged by pencil hard melt freeze crust above. The biggest concern moving forward into the next storm is the widespread layer of buried surface hoar.

North Aspect, 8000'
Poor Snowpack Structure

SW aspect, 7800'
Buried Surface Hoar present

North Aspect, 8000'
Example of area holding buried surface hoar

Evidence of past wind loading and minor cornice development

Looking south onto Salmon-Challis from Stateline Yurt

Advanced Information

Cloud Cover:

Mostly Cloudy

Temperature:

29F

Wind:

Light , N

5cm (2 inches) of new snow overnight. Light wind, no transport noted. Average snow depths along the state line were between 70 and 80 cm (25-30 inches).

Today we dug one full profile and multiple test pits around the compass. Not surprisingly, northern and shaded aspects are holding early season snow from October which has advanced towards depth hoar. The thick melt freeze crust above it seems to be bridging it effectively, and I do not anticipate this layer being active until we add a significant load to the snowpack.
My biggest layer of concern moving forward is a widespread layer of buried surface hoar found on all aspects. The only areas where we did not find this layer were in tight green timber. Surprisingly, we also found this layer in areas where I would have expected it to be destroyed by winds. Currently, we do not have a slab above it to propagate as the surface snow is a layer of noncohesive near surface facets. Once we add a load or a slab to this, expect this layer to fail.