Southern San Juan

Avalanche

Chris Bilbrey · Apr 5, 2023 · Southern San Juan

Weather

Cold and sunny to start. Clouds moved in mid-morning with light snowfall shortly thereafter. Moderate westerly winds contributed to light drifting above treeline.

Snowpack

We found 3 to 4 inches of new snow around 9,500 feet, 6 to 8 inches around 11,000 feet, and close to a foot in the alpine - isolated drifts around 16 inches. The snow in drifted areas near ridgetops was dense/ wind-thickened that cracked at our skis, but small test slopes were reluctant to fail with ski pressure. Kicking small sections of fresh cornice growth onto east-northeast-facing slopes below did not entrain additional snow. In general, we found good bonding between the latest storm snow (F to 4F to 1F-, top to bottom) and varying old snow surfaces - a stout crust on sunny slopes, and either a firm wind-layer on upper-elevation northerly aspects, or a softer old snow surface on sheltered slopes (decomposing fragments and tiny faceted grains). Probing on various aspects up through elevation, we found fairly uniform upper snowpack layers and only subtle changes to hardness. Sampling total snow height on an easterly-facing slope near treeline yielded 325 to 350 cm. The snow surface on east and south-facing slopes below treeline started softening from morning sunshine, but clouds and snowfall limited solar warming. Most aspects stayed cold and dry by the time we exited the mountains midday. New snow amounts below treeline were not deep enough across most terrain to drive an increase in hazard.

Avalanche

No fresh avalanche activity from the latest round of snow. Only old crowns from the 3/22-23 cycle.