Northern San Juan

Avalanche

Chris Dickson · Dec 12, 2020 · Northern San Juan

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Weather

At 10,100’ in the trees: S1 with periods of S2 snowfall throughout day. Total snowfall by end of tour: approx 7cms. Very light winds, swirling in from different directions. Obscured sky cover all day. Warmer and less windy than forecast.

Snowpack

Below treeline snowpack ranged from 40-60cm. Mostly facets throughout, capped with 20cms of new snow. Widespread cracking and collapsing was observed, all on the new snow/old snow interface. New snow showed some soft slab characteristics but broke apart easily.

Avalanche

We were able to produce numerous small D1 avalanches on small test slopes, remote triggering several from up to 20-30ft away. We did not observe whumphs or audible collapses and the cracking that was observed did not propagate far. As this new snow settles and stiffens into a more cohesive slab, we expect this interface to become even more reactive.