I see that this is your first post here poch 5 so welcome to FSM.
Like Smith M said, there is a search function at the top of the page that can get you to all kinds of threads about snow making.
Here's a link to one of them that may get you started.
http://www.finescale.com/fsm/community/forum/topic.asp?TOPIC_ID=3677&SearchTerms=snow
Hope you enjoy the forums !
Happy Modelling and God Bless
Robert