Southern San Juan
AvalancheMatt Entz · Feb 10, 2020 · Southern San Juan
Weather
Light snow falling, temp mid 20s, and light winds from the southwest.
Snowpack
Using east aspect at 10,500 feet for a test slope. Relatively strong snowpack as observed from about 180 cm down from surface. Top 20 cm f hardness with dirt/snow mix layer underneath (new snow from past several days sitting above this layer), next 60 cm 4f, next 60 cm 1f, and everything below that p hardness. We found similar results on the same snow/dirt layer 2 days earlier while digging a pit for layer id with a ct result of CTM16 at 15 cm below surface (165 cm HS). This was on an east aspect at 10,400 feet elevation roughly 2 miles southeast.
Avalanche
Small slab (r1 d1) released between snowmobile tracks 2&3 of a 3 part slope test. Slab was roughly 8” thick with a bottom layer of snow/dirt mix from a wind/snow event on February 3rd. Since that date, snow has fallen on 3 different occasions adding up to about 8” in this area. That snow/dirt mix is not binding well with the interface below. Slope is east facing at 10,500 feet and measured 42 degrees. What is interesting about this series of tests and result is that cross-cutting the slope showed no signs of instability even with 2 separate tracks trenching into the snowpack up to 6’ deep. The 3rd track was a slow descent from the side and top of the slope down towards the 2 previous tracks cutting with the snowmobile on edge. Once sled was within about 10 feet of cross track, small slab broke.