Northern San Juan

Avalanche

Mike Barney · Feb 17, 2021 · Northern San Juan

Weather

Clear skies and cold temps this morning turned overcast by midday with light snow and calm winds.

Snowpack

I traveled in west-facing terrain from 10,000' to 11,700'. The new snow is sitting on a stout melt freeze crust about 30 to 40 cm down from the surface. A few hand pits on the way up showed that the new snow was bonding well to the crust. A northwest-facing crown profile where the snowpack was 101cm deep showed that the avalanche failed about 27 cm from the ground on what I'm thinking is the 12/11 interface (2-4mm facets). This layer was giving us problems earlier in the season but has been unreactive until these last few storm in the alpine. Most of the large avalanches from this week are failing in old facets that formed in December.

Avalanche

This natural avalanche ran sometime yesterday afternoon after the storm stopped and winds started. Its crown is about 250' wide and and varies from about 8' at its deepest point to about 2' at its thinnest. It ran from about 12,500' to 10,400' and debris was estimated at 8' deep and over 300' wide in areas. It is coded: HS-N-R2-D3-O