There Tomi told, the way he made that snow. It`s baking-soda, and gently sprayed water over soda layer. After that, he have painted soda layer with white house paint. He repeated this 2-3 times , so snow comes "clumpy"
I have made snow mixing white glue with baking soda, and sprayed matt varnish over that snow.
its worth to try if its works.
I hope you find out what I'm trying to say with my english....