Are there any areas that were clean and bare of snow prior to this Pine-Based Snow, yet not being affected by the P.B.S.? (wait, PBS is already taken...
)
If so, you could take a core from that area, melt
it and report that as your value.
If there was some way to judge that the true snow (from the sky) was a "Trace", you could report that.
If you can't isolate the stuff from the trees, this is indeed a toughy....
Greg H.