Professional Observation

Observation Details

Signs of Unstable Snow

Key Points

We toured into the Mammoth Lakes Basin today and found efficient travel, beautiful weather and reason to stick to terrain with lower slope angles, deeper snowpacks, and relatively low consequence.

• Surface Hoar has been growing on the surface in protected areas and we witnessed grains up to 6 mm in. size
• I got a good look at a few avalanches that occurred along the Mammoth crest during our last storm event, and I am feeling confident that things broke down to the 12/01 PWL or even to the ground.
• We dug in at 10400’ on a N aspect and found a reactive snowpack with Poor structure. Stability tests highlighted 2 layers of concern. The main layer of concern is the 12/1 interface with 1F+ slab resting on 4f large, grained facets near the ground. I also saw propagation on my ECT test in the mid pack below a P+ wind board layer. (see pit for more details)
• We noted decent surface faceting and a renewed potential for small loose dry sloughs in steep unsupported terrain.