downfall vs snowfall

downfall and snowfall both are nouns.

Word	Noun	Adjective	Verb	Adverb
downfall	Yes	No	No	No
snowfall	Yes	No	No	No

As nouns, snowfall is a hyponym of downfall; that is, snowfall is a word with a more specific, narrower meaning than downfall:

downfall: the falling to earth of any form of water (rain or snow or hail or sleet or mist)
snowfall: precipitation falling from clouds in the form of ice crystals

Other hyponyms of downfall include fine spray, hail, rain, rainfall, sleet, snow, virga.

downfall (noun)	snowfall (noun)
a sudden decline in strength or number or importance	precipitation falling from clouds in the form of ice crystals
failure that results in a loss of position or reputation
the falling to earth of any form of water (rain or snow or hail or sleet or mist)