Would be great if the clear terrain action cleared snow from the current tile. I attempted to do it on a junk pile, to find not only did it leave the snow but it cleared away the junk pile! Not sure why anyone would want to do that but maybe first use clears snow, 2nd clears the junk? Haven't really tried this yet but I'd assume snow greatly reduces your speed, and roads have no benefit when covered in snow, so clearing roads of snow would be important.