The falling snow on Mountain Pass accumulates on stationary tanks. This a great effect. The longer you sit still the thicker it gets on your tank.
However, when you move the snow comes off. So, I really only get to see it at the start of the match. I am moving and other tanks are normally moving too much during the match for snow to start to build up again.
My suggestion is to keep 25-30% of the snow on the tank once it accumulates. Have 25-30% the minimum amount of snow when you are moving around, even full speed. I am not really looking for "realism" but just something interesting. Although the snow on tanks could help with concealment in CW with True Vision.