Southern San Juan

Avalanche

Chris Bilbrey · Mar 17, 2023 · Southern San Juan

Weather

Friday was a beautiful day in the mountains – cool temperatures, light wind, and sunshine. Scattered clouds on Friday helped filter the strong sun and kept snow surfaces from warming too quickly.

Snowpack

Settled new snow depths ranged 40 to 50 cm. A mostly 1F hard slab contributed to efficient travel. Ski penetration ranged 10 to 15 cm in a 4F hard layer of decomposing fragments on northerly-facing slopes. A thin surface crust exist on east, southeast, and south-facing slopes near and below treeline. This breakable layer likely formed during periods of sun on Thursday as the storm cleared. Digging on an east-northeast-facing slope around 11,600 feet yielded fairly homogenous upper snowpack layers and good bonding. The most obvious/ concerning weak snow layer (2/14 Interface) resided around 90 cm deep and is 1F- hardness. Snowpack tests produced CT PC 10/12 in the top 20 cm at a density change, and CT SC 24/ 25 at the new/ old interface (1 cm crust with tiny 4F PP and NSFs below). We observed inconclusive results on the 2/14 interface - one test produced a CT SC 28 and the second test did not fail at this layer. Lots of wind-texture/ smoothing of the snow surface on windward slopes above treeline, but we did not encounter stiffer slabs at treeline or below ridges where we traveled.

Avalanche

Numerous Loose Dry avalanches (size 1-1.5) running on steep, sunny slopes in the alpine (east to south). Slides appeared confined to recent storm snow and likely slid above a crust.