Southern San Juan

Avalanche

Chris Bilbrey · Dec 29, 2021 · Southern San Juan

Weather

Light snow in the morning transitioned to broken skies and about 3 hours of no precipitation. By 1:30 pm, snowfall resumed increasing in intensity (S2) by late afternoon. Daytime accumulations up to an inch.

Snowpack

We found varying snow depth on multiple aspects in our travels today. Snow depths ranged from 100 to 130 cm's on southerly-facing slopes below treeline. These slopes lack old snow at the ground and the snowpack is generally right-side up. No concerning layers identified in hand pits. On the north side of the compass up to about 11,200 feet, snow depths ranged from 150 to 200 cm's. Facets at the ground remain weak and still reactive from the weight of the overlying slab. Propagation Saw Test produced failures in weak facets/ depth hoar and the crack propagated to the end of the column, PST End 40/160. Places where old snow is buried deeper have become harder to initiate failure, but the consequences are now bigger. Closer to the surface, a near-surface facet layer developed on top of a dust layer that blew in on December 27. While it took hard force to initiate propagating across the column and fractures were dirty, this layer could become a bigger problem once the overlying slab settles and stiffens or more water weight is added above.

Avalanche

Lots of small, natural loose sluffs on northerly-facing slopes around 35 degrees or steeper. No recent slab avalanches observed although visibility was poor today into alpine terrain.