WordNet (r) 3.0 (2006):

snowfall
    n 1: precipitation falling from clouds in the form of ice
         crystals [syn: snow, snowfall]

Moby Thesaurus II by Grady Ward, 1.0:

39 Moby Thesaurus words for "snowfall":
   avalanche, blizzard, crystal, driven snow, flake, flurry,
   granular snow, igloo, mantle of snow, mogul, slosh, slush, snow,
   snow banner, snow bed, snow blanket, snow blast, snow fence,
   snow flurry, snow roller, snow slush, snow squall, snow wreath,
   snow-crystal, snowball, snowbank, snowbridge, snowcap, snowdrift,
   snowfield, snowflake, snowland, snowman, snowscape, snowshed,
   snowslide, snowslip, snowstorm, wet snow