Northern San Juan
AvalancheChris Dickson · Oct 28, 2021 · Northern San Juan
Weather
Early morning north winds tapered off as the day dawned under bluebird skies. Lots of spindrift coming off all the peaks from that north wind. Temps quickly warmed up in the Fall sunshine and big rollerballs were observed on the solar aspects.
Snowpack
Snow depths varied from 20-40cm below treeline to 70cm at treeline. Below treeline, not much wind effect on the snow, but above treeline, the snow surface was a punchy windboard with small sastrugi. Dug in at treeline and observed 70cms of total snow, with 40cms of new snow, sitting on a graupel layer (likely dropped at the start of the storm, which featured thundersnow!), sitting on a faceted out crust, sitting on rounding facets to the ground. This new snow is settling into a F to 4F slab on top of that crust/facet combo, which will likely linger as our PWL. No stability tests were performed due to the tight timeline of the tour....
Avalanche
Observed several D1 chunky loose dry avalanches coming out of steep N-facing couloirs, evidence of the wind transport that occurred during the storm.