Southern San Juan
SnowpackChris Bilbrey · Jan 31, 2021 · Southern San Juan
Weather
Overcast skies and strong southwest winds Friday afternoon. Snowfall started around 8 pm Friday night with moderate winds all the way to valley bottoms. Overnight, new snow accumulations of about 4 inches at 9,000 feet and up to 12 inches near 11,000 feet. Skies were mostly sunny on Saturday with moderate to strong northwest winds drifting snow in the alpine. Sunday was clear, calm, and slightly warmer than Saturday which contributed to an uptick in loose dry sluffing on southerlies.
Snowpack
On Saturday, we found generally good bonding of the storm snow on north-facing terrain below treeline. No cracking or collapsing observed. Strong northwest winds Saturday were drifting snow onto leeward slopes in the alpine contributing to a few natural wind-slab avalanches. We also observed several loose dry sluffs running a long distance on east and southeast aspects from daytime heating. There were a number of older crow lines that looked to run during the big storm cycle between 1/22-26 on east and northeast aspects. As we climbed higher in elevation, we could easily identify weaker snow below a cohesive upper slab while probing across slopes. Steep, open and wind-loaded pockets on slopes facing north to east still seem the most suspect and likely spot to trigger a slide below and near treeline. Southerly slopes were forming a 1/2 to 1 inch thick crust with soft, drier snow below.