Northern San Juan
AvalancheJason Bushey · Jan 1, 2020
Weather
Snow all day. 2-3” of new snow in 5 hours. Snow coming in sideways at times. Wind swirling in multiple directions, but not moving old snow much and did not observe any peeling of Saturday’s snow at and above treeline.
Snowpack
Throughout day minimal signs of unstable snow below treeline or at treeline on N to NE terrain. As well as test slopes on E and W aspects. One ski cut created avalanche below treeline 20’ across and showed a reactive layer 18” from surface but did not see this react or show the remainder of day and expect this was from Sunday or Monday. No recent avalanches seen. Hand pits were unreactive with no slab properties down 40 cm. Skin cuts and switchbacks all supportable. 30cm ski pens. As we approached west alpine terrain at 12,300 to 12,500’, this changed rapidly. 2-3” windslabs were reactive at times creating 15’ shooting cracks and one D1 avalanche 15’ wide and traveling 25’ down on a 35 degree slope. This was reactive on crust layer from yesterday. On NE aspect wind slab also reactive at 12,500’ (explained below).
Avalanche
R1D2 intentional skier triggered, from ski cut. Avalanche ran 12,500 to 11,000’, 20-40’ wide. NE aspect, 38 degree slope. 6” deep at crown reacted on wind slab from Monday or Tuesday but do not expect from today. Did not step to lower layers of snowpack and bed surface soft after. Image is crown.