Southern San Juan

Avalanche

Chris Bilbrey · Mar 7, 2022 · Southern San Juan

Weather

Periods of light and heavy snowfall throughout the day. Skies remained overcast to obscured with brief moments of sun. Light southwest winds along ridgetops.

Snowpack

We found about 60 cm (2 feet) of new snow below treeline, and upwards of 75 cm (30 inches) at treeline that accumulated from 3/4 to 3/7. Storm snow was right-side-up and bonding well to the new/ old interface. Snow along ridgelines and in the alpine was slightly wind-thickened, and there we noticed a 20 cm thick surface layer breaking at our skis along the skin track. We did not observe long-running cracks or audible collapses in wind-drifted areas up to about 35 degrees in steepness on north to east through southeast aspects where we traveled. Compression Test produced break failures in storm layers, and resistant planar failures above a dusty crust on a southeast aspect. This crust was a couple inches thick and supportable, with refrozen/ moist rounds below. We found the 2/21 facet layer down 120 cm in a snowpit on a northeast slope at 11,500 feet. This layer did not propagate in Extended Column Test (ECTX). We did observe non-propagating failures in Extended Column Test at each hardness change in the new snow.

Avalanche

Evidence on numerous small loose snow, soft slabs that most likely ran during periods of high PI. These slides occurred on north to east through southeast-facing slopes at all elevation bands.