Northern San Juan

Avalanche

Jason Bushey · Dec 29, 2018 · Northern San Juan

Weather

Cold, -12 at the parking lot at 10am. Clear skies, and a North west wind approx 15-20mph at ridgelines in afternoon. No wind experienced below treeline. Sun at times was intense, but cold temperatures prevailed never visibility warming the surface of the snow. Was 5 degrees when finished tour at 5pm.

Snowpack

HS95-125 on NW aspects. Below treeline snowpack was extremely unconsolidated, often times with boot penetration to the ground. As you travelled above treeline, the snowpack had more consolidation in the upper pack, with anywhere from 30-50cm of facets from the ground. Dug pit at 11,800, aspect 290, 28 degree slope. HS 125, with ECTHP at 50cm on the facet layer. CTMQ1 resistant planar at 90cm, and CTMQ1 at 50cm. Spacial variability exists, with treed areas experiencing a shallower snowpack around 50-70cm in places. On NW aspects above treeline near ridgelines, experienced firm thin snow from previous wind stripping. Experienced large shooting cracks at 11,800' below treeline on NW aspects on second lap on establish skin track. This was on a 25 degree slope after 8 people had already passed it that day 2 hours prior. Also experienced shooting cracks over 100' on NW aspects below treeline in low angle wide unsupported areas.

Avalanche

Multiple expected natural avalanches found, unless bombing was occurring on the previous day from silverton mountain, but could not see bomb holes, and no active bombing on 12/29. Natural Avalanche were see on SE aspect, 11,500' R1D2 E aspect, 12,800' R3D2, with old debris from previous slide NE Aspect, 11,800' R3D2