Northern San Juan

Snowpack

Eric Roberts · Jan 30, 2021 · Northern San Juan

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Weather

Few trending to scattered by 14:00 Calm trending to light N winds, with flagging observed on Anvil ridgeline 23°F at 9,800’ (13:00) 17°F at 10,490’ (15:30) S-1 consistent from 13:00-17:00 No cracking, collapsing or observed releases

Snowpack

In general, my focus was to assess instability and current structure of the snowpack. Tests at 10,490’ showed low to moderate strength, poor structure and strong propagation propensity. From 9,500' to 10,000': 4-6" of new, low density precipitation particles, over settled F+ wind stiffened snow. From 10,000' to 10,500' 4-6" of low density over F hard settled snow A temperature gradient is present within the lower snowpack, which is very evident with the observed depth, thicknesss, distritubtiuon and grain size of the advanced facets. There is a distinct spatial variance within the basal ice layer over talus, specifically producing failures at isolation (See photo) where no basal ice is found, just 4-6 mm depth hoar, and low to moderate results where K-hard basal ice is found. The basal ice is ingrained within the talus in sporadic locations. (See Photo) See Snowpilot for details