Developing avalanche problem
Monashee Mtns. - Mt. Macpherson Fingers
Today was a "Fingers" day on Mt. Macpherson. It was snowing less than a centimeter and hour when we arrived in the parking lot with approximately 15cm new overnight - by the time we left(we were back at the car by 11:45) it was snowing 3-5cm/hr and the snow felt like it was starting to warm up.
At the elevation of the ski terrain, we found 45cm of soft snow (Fist to 4F resistance) over a crust. There was an obvious weakness where the overnight snowfall rested upon the previous snow surface down about 20 cm. in the morning (probably reaching 30 cm depth by this afternoon with current snowfall rate).
By the time of our last run this weakness was reacting to our skis on the short steep features we encountered during our descent, sometimes even remotely. We intentionally avoided a known steep roll in our ski line as we were sure it would release as an avalanche given the developing slab properties of the new snowfall.
We saw a couple of new small (size 1) avalanche deposits in the morning that had run a fair ways for their size.
Therefore we were both very wary of the overhead hazard today (hence our early departure), there is a lot of snow available to move once things get started.
As a result we were stopping well short of what would be our usual topout elevation, and stuck to moderate angle slopes which provided some great skiing.
I wouldn't be surprised if there is a natural avalanche cycle in the paths later today as the storm snow accumulates and the forecasted warmup continues.
Changing conditions create more uncertainty and will require us to make some smart choices while this next set of storms loads the snowpack.
ACMG Mountain Guide