Northern San Juan
AvalancheAnn Mellick · Dec 12, 2020 · Northern San Juan
Weather
Wintry with cold temps, snowfall and intermittent winds. Less wind than expected, even above tl.
Snowpack
We are up to 15" new snow as of late this afternoon. This has settled to an average of 7"-10" in most locales, with drifts up to 2 feet deep near and above treeline. New snow sits on the well-advertised very weak faceted snow that formed near the snow surface during the recent prolonged dry spell. This interface proved quite reactive to skier pressure today and is the area of greatest concern. Below treeline, I only noted localized cracking around skis, but lots of large shooting cracks (running up to 40') and rumbling collapses near and above treeline. The snow near and above treeline is much more wind affected, with pencil hard slabs sitting on Fist to 4 Finger snow below. Steep terrain facing E->N->W is to be avoided. Southerly slopes don't have the thick layer of facets and are less reactive. Snow was also less reactive below treeline, but human triggered small slabs and dry loose slides were a common theme today.
Avalanche
Touchy conditions with a solid new load on a weak upper snowpack