Northern San Juan

Avalanche

Jeff Dobronyi · Dec 2, 2024 · Northern San Juan

View on map
Observation photo 1Observation photo 2

Weather

Light W winds, warm temps near freezing, no blowing snow, FEW clouds

Snowpack

HS 80-90cm BTL, 100-120 NTL, highly variable ATL. BTL snowpack is entirely faceted on shaded aspects. IFcr widespread on solar aspects. November Bulletproof Layer (NBL) present on polar aspects NTL and ATL, down about 35cm where we travelled. Boot pen was 35cm. ECTPx2 (21, 24) down 70 below NBL in middle of November facets, this interface was hard to see with naked eye, perhaps buried NSFs slightly larger than FCs around it. 11/26 interface seems well-bonded here, no fractures on this interface in ECT or shovel shear tests. No signs of instability other than 11/26-27 natural cycle. Many tracks in steep terrain.

Avalanche

Many naturals from 11/26-27 cycle, all on polar aspects. Wide propagation but rarely larger than D2 debris piles, all looked like soft slab debris, and only a small percentage of the avalanches seemed to involve the november facets.