Southern San Juan

Avalanche

Mike Barney Chris Bilbrey · Nov 8, 2020 · Southern San Juan

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Weather

Today's cold, snowy weather was a welcomed sight after a dry fall. Winds were light at pass level but increased with elevation. Periods of light snow didn't add up to measurable accumulations. Skies were a mixture of broken to overcast to obscured.

Snowpack

New snow depths ranged from 15 to 20 inches with drifts near 3 feet deep at higher elevations. Slopes where the recent storm snow fell onto bare ground (E-S-W) showed good bonding and overall good stability. We encountered shallow storm layers on those same aspects that were reactive but non consequential and did not travel far. Northerly-facing slopes where old, October snow lingers are the most concerning. We observed numerous shooting cracks propagating outward about 50 to 100 feet wide where a thick layer of weak, faceted snow sits below the dense storm snow. This slab, weak layer combination was not found on all slopes and varied in thickness across the same slope. Extended Column Test (ECT) produced propagating failures where old snow was present. Shallow and stubborn wind-drifted slabs were starting to form near and above treeline in leeward terrain features and we expect these to grow in size and distribution with additional snowfall in the next 24 to 36 hours.

Avalanche

None observed.