Grand Mesa

Avalanche

Matt Huber · Mar 21, 2021 · Southern San Juan

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Weather

Heavy snow showers in the morning quickly ended with only. a few flakes of snow and graupel falling after 10:00 am. Southwest winds were strong enough to transport new snow onto northeast-facing slopes, building small cornices near ridgelines and stripping windward slopes to the melt/freeze crust below.

Snowpack

Southwest winds built reactive but small cornices and 10-20 cm slabs at and just below exposed ridgelines near and above treeline. These were all relatively harmless. Several crusts are obvious in the upper meter of the nearly 3 meter deep snowpack. The most reactive is a crust facet combination 75 cm below the surface, extended column test produced hard propagating results here, ECTP22. The warm temperatures and percolating water last week made it down to this layer as well but the rest of the snowpack remains dry below.

Avalanche

I was able to produce very small and harmless wind slab avalanches on no consequence test slopes near treeline.