Southern San Juan

Avalanche

Chris Bilbrey · Dec 22, 2020 · Southern San Juan

Weather

Overcast and light winds to start. By mid-afternoon, winds increased and remained steady out of the southwest with light flurries and drifting snow above treeline.

Snowpack

Snow depths range from around 60 to 90 cm's below and near treeline. In the alpine, we found drifts around a meter deep or slightly more. The lower snowpack is not showing any signs of strengthening and actually seems weaker and more fragile then our last visit to this area. Snowfall since December 11th has more cohesion, is in general harder than buried facets below, and this made for trap-door riding conditions near and below treeline. Collapsing and shooting cracks have subsided below treeline but not fully gone. Once we climbed into the near treeline band and got into more wind-drifted snow, the collapses and shooting cracks returned. We observed too many collapses to count and one crack shot outward around 100 feet across an open, northwest-facing slope. No slide ensued. Steeper areas around cliff bands with extensive faceting below recent storm snow easily sluffed with ski pressure, entrained more snow moving down slope, and picked up speed rather quickly. In the alpine, we found a shallower surface slab (the lower portion a 1F wind-drifted layer) sitting above about 10 cm's of facets. These facets were harder and less advanced as lower in elevation and the firm wind-drifted layer above the facets seemed to prevent our stability test from failing in this layer. Only time will tell how much of a new load the 1F layer will support before failing. We found this setup ranged from 1 to 2 feet below the surface across alpine areas.

Avalanche

None observed.