Northern San Juan
AvalancheJeff Davis · Feb 18, 2018 · Northern San Juan
Weather
Strong SW winds observed at all elevations. The sky was clear in the morning, but clouds developed throughout the day. Temperatures were mild and above freezing at lower elevations.
Snowpack
Strong SW winds picked up overnight and continued throughout the day. The wind was strong enough to move any available snow onto northerly and easterly slopes while stripping windward slopes. Winds were so intense that plumes were likely sublimating while lower start zones loaded. The newly loaded snow was creating a small 1 finger surface slab near-treeline that will become an issue as it gets overloaded. Slabs above-treeline were likely thicker and stiffer. Well developed weak-layers persist within the top meter of the snowsurface on many slopes. A natural avalanche cycle was observed on leeward slopes in the morning hours. The wind helped keep the snow surface cool at upper elevations, but warm temperatures and strong solar warmed the snow below ~11,000'.
Avalanche
A natural avalanche cycle observed. Large avalanches were observed in the Bear Creek, on Sunshine Mountain, Lower Commodore, Trico area, and near Lizard head pass.