Northern San Juan
AvalancheJeff Davis · Dec 11, 2019 · Northern San Juan
Weather
Clouds developed during the day Temperatures were in the mid 20's with southwest winds near and above treeline, but calm at lower elevations.
Snowpack
HS ranged from 50- 100 cm's. Widespread surface-hoar and near-surface facets were observed in the morning on the snow surface. A pit on an East facing slope around ~12,000' showed a slab sitting above facets at the bottom of the snowpack. Two long column tests showed failures on the buried facet layer, but did not propagate. ECTN25x2 I triggered a small Storm Slab avalanche on a steep NE facing slope in the gully. Collapsing was also observed while exiting the area through a gully feature.
Avalanche
A skier triggered a small D1 Storm Slab avalanche on the exit in the gully on a northeast facing bank. Two natural avalanches observed today that likely ran during the past weekends storm December 8th, 2019. Henrietta's northeast R1 D1.5 and J chute north R2 D2. Both broke as storm slabs, but did not step down to lower layers.