Snow Grains : These are a precipitation comprised of very small white and opaque grains of ice. These grains are fairly flat or elongated; their diameter is less than 1 mm. When they hit hard ground, they do not bounce or shatter
Transport Canada, TP 10643 -When in Doubt. Small and Large Aircraft - Aircraft Critical Surface Contamination Training for Aircrew and Groundcrew, Glossary 7th Ed., Ottawa, ON, Canada 2004, http://www.tc.gc.ca/eng/civilaviation/publications /tp10643-glossary-1116.htm, (Avn Sfty - Canad) {652}