Vail & Summit County

Avalanche

john morrone · Dec 10, 2019 · Vail & Summit County

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Weather

11,000', W, sheltered open forest and glades bluebird, w 5-15, stronger at ridgeline, 25 F, some solar wetting on surface at noon

Snowpack

vail pass below uneva ridge 11,600'-10,800' west exposure 20 degrees HS 60-80 CM snowpack only supportive where old tracks existed. boot pen to ground (32"-80cm), ski pen 20 cm surface covered in surface hoar up to 4-5 mm in sheltered locations. top 25 CM cold low density storm snow, loose, only beginning to become cohesive after noon warming. quick pits indicate basal 20 CM facets loose, weak, fist soft covered by significant MF layer 5 cm thick (Knife?). another faceted 10 cm layer under a weak MF crust on open W exposures ski compaction on this overused slope did NOT penetrate to basal facet layer, but only above the overlying crust layer where investigated.

Avalanche

recent E-SE slab ( 1.5?) SS with clear slab crown just below cornices with current lee wind top loading. likely natural either cornice collapse or windloading trigger