Northern San Juan
SnowpackMatt Steen · Dec 20, 2012 · Northern San Juan
Weather
A beautiful day. Clear Skies with temperatures raising through the afternoon.
Snowpack
The snowpack on westerly aspects below treeline is shallow (1-1.5 feet) consisting of recent storm snow resting on a thin layer of faceted snow at the ground. Collapsing and cracking was present on these westerly facing slopes below treeline. Near treeline, previous westerly winds drifted snow onto north through east facing slopes. Wind slabs were present behind terrain catchments including tree islands and behind ridge crests. Wind slabs quickly softened to persistent slabs only 10 to 20 feet below lee ridgelines. Collapsing a weak layer under a wind slab, triggered persistent slabs on lee north through east facing slopes. Persistent slabs (2-2.5 feet) resting on weak layers of buried facets were present on north through east facing slopes below treeline. Collapsing and cracking was widespread on these aspects. Earlier, skiers did trigger an avalanche on an east facing slope below treeline.