Southern San Juan

Avalanche

Chris Bilbrey · Apr 27, 2021 · Southern San Juan

Weather

Classic spring storm...snowing and blowing one minute followed by overcast skies then short breaks of sun. Wash and repeat. Snowfall during our tour maybe amounted to an additional half inch or inch of snow. Moderate southerly winds above treeline contributed to light drifting and shallow soft slab formation.

Snowpack

We found around 4 inches of new snow at pass level and up to 6 inches by the time we climbed above 11,000 feet. Stronger winds in the morning aided light blowing snow and drifting in the alpine. We found isolated, reactive, but shallow wind-deposited slabs on the back side of steep rollovers and on cross-loaded terrain features. These conditions were more pronounced on north to east aspects. Deepest drifts were in the 8 to 10 inch range. Warm temperatures and a moist old snow surface at the onset of snowfall helped the new snow bond well to the refrozen crust below. The new snow was setting up quickly and settling faster than accumulating during the day. The new snow on lower elevation slopes felt like styrofoam by late afternoon.

Avalanche

Small loose dry sluffs with periods of sunshine and a couple shallow, skier-triggered wind slabs on steep convexities in the alpine. All were non-consequential in the terrain we traveled.