Northern San Juan
AvalancheJason Bushey · Jan 4, 2020 · Northern San Juan
Weather
Not as warm as expected, with alpine temperatures hovering around 20-25 degrees and solar activity playing little impact on the typical solar aspects. No roller balls seen on SE aspects at treeline or below, and no glopping of skins on E aspects below treeline at 11,000' at 1pm. Winds continued to come out of the north in the morning, but then switched for a short period with large gusts from the S around 2pm. Winds looked to increase after 3pm at the car.
Snowpack
Winds from the North did work on ridgelines. Snow depths were variable above treeline on north aspects around ridgelines, with spots of 40cm and some of 160cm within a 15 meter radius. Shallower depths were primarily made of facets and weaker snow but limited slab formation on top and if so were easily visible on north aspects. An unconventional (and not recommended) ski test of a ski falling off down a run which resulted in one foot skiing for a hundred yards in a shallow area showed no wind slab formation on North aspects of shallower snow. We stuck to the deepest depths of north aspects for 2 ski runs (36-40 degrees) from 12,200' down below treeline. Once off ridge lines, the snowpack was a bit more consistent and supportable. We all agreed that with the next load, the start zones of north in shallow areas today (such as rock outcroppings) could cause problems of concern tomorrow, and these aspects may be tough to see next time around. E aspects of ridge lines were 1/2" ski pen, very firm and textured. Wind slab formation seemed to occur on this as well as SE aspects. SE aspects verified with hand pits and pole plants a melt crust on top of weak snow around 12,000'. Avoided steep terrain on this aspect. And below treeline is still bomber on N and E aspects.
Avalanche
One D1 soft loose avalanche released naturally on N aspect 12,000' at a rock outcropping. 5' across by 50' in length and very shallow.