To create falling snow on a card use masking fluid. Flick masking fluid with a tooth brush. When dry, sponge on color.
Watercolor Painting "All About Masking Fluid" - FREE Tips'n'Tricks lesson - by Annette Raff
Sneak Peak into "Mastering Twinks": short tutorial in creating a painted butterfly using paints and masking fluid. Must DO this!
New Art Journal Page - Inking Masking Tape for Texture