Though I am no professional compared to many others here, Shermanfreak I believe gave you some excellent links the first time you posted in the forum asking about paints. One of those links had a great article on weathering and one of those tips also dealt with snow camoflage. (It was basically a wash using ground up chalk and water. Once the water dried, you could dry brush the model to weather it and lessen the overpowering effect of the "snow" and then if satisfied, you could then apply a dullcoat finish. If not, wash it off with water and start over. ( I learn something new everyday with these guys!) Check it out and good luck!
Roy