I did a tutorial on creating a set of bouncing balls using a particle system, in that tutorial I showed how the particles could be replaced by any object, to illustrate the point I used the monkey head.
In this tutorial the particles are replaced with a model of a snow flake. Then it is a matter of experimenting with the settings of the particle system and the collision properties of objects the flakes hit to give the most realistic or fun effect.
Click here for the files – snowFlake3.blend snow2.blend
The following is the tutorial that shows how to make a model of a snow flake -
The following tutorial show how to use the model of the snow flake with a particle system to make a snow effect -
The following video shows the snow effect rendered -
