Southern San Juan
AvalancheChris Bilbrey · Jan 19, 2023 · Southern San Juan
Weather
Crisp, sunny day with light winds along ridgetops.
Snowpack
In the last 24 hours, recent storm snow has settled a lot. Two days ago, trail breaking, in general, ranged from boot top to knee deep. Today ski penetration was around 6 inches deep. Probing across southerly-facing slopes revealed a mostly right-side-up storm slab. Our snowpits on southeast-facing slopes below and near the treeline confirmed these findings. We observed moderate to hard Compression Test failures within storm layering and at the January 14 faceted crust interface, and Extended Column Test near the treeline produced non-propagating failures in a 4F layer below a 1F drifted slab around 8 inches thick. Probing across northerly-facing slopes below the treeline, we could feel more discernable differences in storm layers but did not see any surface cracking or audible collapses. Nonetheless, the overall storm snow felt mostly right-side-up on northerly aspects, and persistent weak layers of concern are buried more than a meter deep and in some instances, up to two meters deep in the Deer Creek zone. The snow surface on sunny slopes started out dry and fluffy, but isolated areas were developing a thin zipper crust by midday. No rollerballs or loose snow sluffing observed on our travels and probably influenced by cold air temperatures despite direct sunshine. We exited the mountains around Noon before peak heating likely occurred.
Avalanche
It appears that with each subsequent big storm load, we are observing fewer avalanches. The fact that slides continue to fail into old snow layers suggests that finding a thin spot on a slope could still produce a large, dangerous slide - lower probability/ higher consequence scenario at present.