Southern San Juan

Avalanche

Chris Bilbrey · Dec 28, 2022 · Southern San Juan

Weather

Heavy (S2) snowfall till around 8:30, then a big sucker hole sat over the Coal Bank Pass area for about 2 hours. Light snowfall (S1) started again late-morning with generally light winds throughout the tour.

Snowpack

The new snow fell right-side-up (F to 4F, top to bottom) with a subtle, dirty density change about 4 or 5 inches below the surface. Not a lot of audible collapses on our travels except on easterly slopes with a faceted crust below the storm snow. Compression Test (CT) produced sudden planar failures with a moderate force below the crust. Drought facets are slowly being buried deeper on north-facing slopes below treeline - 80 cm below the surface around 10,700 feet. These faceted grains yielded sudden planar failures in CTs with mod-hard force but non-propagating results in Extended Column Test. These inconclusive results point to a stubborn slab, weak layer scenario and require additional evaluation, especially with another major storm knocking on the doorstep. As we traveled through drifted areas and around steeper rollovers, we noticed cracking below our skis in the storm slab. The slab showed reluctance to move downhill. These conditions have the potential to change in the coming days with additional snow load or settlement of the storm snow into a stiffer slab.

Avalanche

None observed. No visibility into bigger terrain.