From AMS Glossary
Revision as of 19:53, 26 January 2012 by Perlwikibot
Snow raised from the surface of the earth by the wind to a height of less than 6 ft above the surface.
In aviation weather observations, drifting snow is not regarded as an obstruction to vision because it does not restrict horizontal visibility at 6 ft or more above the surface. When snow is raised 6 ft or more above the surface, it is classified as blowing snow.