I dug a pit to see how the new/old snow interface at the dirt layer was reacting and see if I could find any remnants of the PWL. I dug on a 35° east facing slope at 9640'. The total height of snow was 10' (310cm).
The weakest layer was the new/old snow interface that was reactive with propagation (ECTP 7 and ECTP 10) 9.8"(25cm) from the surface. This is the same layer that I believe was the failure point in the above avalanches. The other result that got my attention was failure with propagation 21.5" (55cm) down from the surface. This layer failed on small grained faceted crystals associated with a decomposing melt-freeze crust (ECTP 27 and ECTP 28). This is the layer that gets my attention for creating much larger avalanches.
Below photo showing pit wall with failure plane at 55cm from the surface and dust layer 25cm from the surface. Everything above the dust layer was new snow and there was an inch of graupel mixed with the dust.
