No, you cannot use baking powder as snow, it will not stick together well enough to throw at your kid brother or older sister. It will not stick together well enough to make a snowman. You cannot hold out your tongue and let baking soda melt on it - well, you can, but it doesn\'t taste right.
lol
Go to the R/C car/plane store. Look around at all the neat toys. Ask for a bottle of micro-balloons. The bottle is not empty - be careful when you open it. The stuff is inert, but I would not recommend inhaling a bunch. Use that along with white glue and a bit of water.