Southern San Juan

Avalanche

Chris Bilbrey · Dec 31, 2018 · Southern San Juan

View on map

Weather

Steady snow and cold (temps below 10 F throughout) created plenty of "cold smoke" snow with limited wind-loading during our tour. 10"HN/ 0.5"SWE at 11,850 ft.

Snowpack

Continuous snowfall during the day accumulated close to 12 inches of new snow by the end of our tour. Cold temps made for low-density snow and little water weight (0.5" SWE) compared to depth. Observed isolated cracking and one noticeable collapse. Natural cracks noted on steeper, convex terrain. Light winds with moderate gusts along ridges did not contribute to significant wind-loading. Weak layer structure is nerving in this portion of the South San Juan zone, but snowpack still lacks a cohesive enough slab to communicate failure in weak layers. Compression test easily highlighted weak interfaces, while ECTs produced non-propagating results.

Avalanche

Triggered a small storm slab up-slope of a steep northeast-facing gully wall.