Southern San Juan
AvalancheChris Bilbrey · Mar 3, 2021 · Southern San Juan
Weather
Sunny day with a light, but steady breezes near treeline and along ridges. Today's wind kept snow surfaces from warming too much and wet snow concerns did not materialize today.
Snowpack
We found a supportable upper snowpack on the majority of aspects near and below treeline. Snow surfaces were a mix-bag of melt forms and crust on sunny slopes and faceting snow on northerlies. In addition, open slopes near treeline had a 1 to 2 inch wind-board on the surface with near-surface facets below. Slopes that face east through south to west got soft and moist, but surface warming only penetrated down around 5 to 10 cm's. Digging on a northeast-facing slopes near treeline confirmed a thick, stiff slab sitting above several layers of weak, faceted snow. We dug adjacent to a large avalanche that most likely ran during mid-February failing on a layer of faceted snow. ECTs today did not yield results in the same weak layer, but lingering weak snow below a thick slab is a logical concern, especially during a big loading/ storm event. The top 10 cm's of snow on northerly-facing slopes near and below treeline has faceted and weakened during our recent string of warm, dry weather. The unconsolidated snow surface will most likely struggle to support a new storm load and rider triggering will become easier.
Avalanche
Saw a couple older avalanches that most likely ran in mid-February. Slides were on north and northeast aspects near treeline and size 2.