Northern San Juan
AvalancheMatt Huber · Dec 20, 2020 · Northern San Juan
Weather
Mostly clear skies and warm temperatures. No visible blowing snow on the highest ridges and peaks
Snowpack
Shallow and weak. 10 to 15 centimeters of recent snow sitting on weak, non-cohesive facets and large depth hoar. A visible change in grain size about 20 cm from the ground but no definitive hardness change produces propagating extended column tests with 4-6 taps from the wrist. The upper snowpack provides just enough structure to support propagation. Shooting cracks, visible collapse and whumpfing are widespread below treeline but volume is limited
Avalanche
The size of avalanches has noticeably increased over the past few days. Multiple D2.5's on east-facing slopes above treeline and a D3 along an above treeline, southeast-facing ridge west of Blackwall Mountain. Many debris piles that must have run earlier in the wind-event with no visible crowns.