Northern San Juan
AvalancheColin Mitchell · Jan 2, 2022 · Northern San Juan
Weather
Beautiful day in the mountains. Very light winds and warm temperatures, even above treeline.
Snowpack
Snow depths in US basin were highly variable, from 15 cm to 3 meters. The snowpack was generally characterized by a stiff slab overlaid by 15-40 cm of soft, wind-buffed snow. We had a few small collapses in the willows at the entrance to the basin, and one large rumbling collapse at the head of the basin on a NW aspect at 12,150 feet. The depth of snow here was over two meters, and the collapse crossed the entire valley floor, around 1200 feet in diameter.
Avalanche
We saw several large, hard slab avalanches. 3 on a northeast aspect above treeline that were remotely triggered by snowmobilers on the afternoon of the 1st, and one natural on a SW aspect at treeline. These avalanches were reported by other observers.