Northern San Juan

Avalanche

Colin Mitchell · Mar 19, 2022 · Northern San Juan

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Weather

Clear skies and cold temperatures to start the day. By early afternoon, clouds had started to move in, and we had broken skies and temperatures near freezing. Breezy conditions through the day, but no meaningful wind-loading.

Snowpack

We traveled southwest, west and north aspects near and above treeline. We ascended W and SW slopes to 12,500'. There was a melt-freeze crust up to around 12,000 feet over moist rounds, on a supportable mid-pack. Higher up the crust disappeared. Despite fairly warm temperatures and strong solar input, the snow stayed cold all day above about 11,500. A profile on a north-facing slope right at treeline revealed a deep snowpack, averaging around 2 meters. The February facet layer was down 70 cm and unreactive to snowpack tests. There were two prominent dust layers visible. The upper one, down about 40 cm is beginning to facet on the top and bottom of the layer, and produced propagating results and planar shears with snowpack tests.

Avalanche

We observed two large avalanches on north-northwest aspects.