You can actually use crushed /ground glass for snow effects. "Secret Weapon" has it in their webshop, so I guess local miniature shops will get it sooner or later. As it is really crushed glas, read the safety instructions carefully!
Link to the product: http://www.secretweaponminiatures.com/index.php?main_page=product_info&cPath=37_39&products_id=106
Tutorial: http://massivevoodoo.blogspot.de/2012/07/tutorial-masterclass-snow-effects.html
Link to the product: http://www.secretweaponminiatures.com/index.php?main_page=product_info&cPath=37_39&products_id=106
Tutorial: http://massivevoodoo.blogspot.de/2012/07/tutorial-masterclass-snow-effects.html