It is also a term, smacking of faint
self-contradiction, used commonly in
astronomy to distinguish frozen
water from other solifdified
volatile substances such as
carbon dioxide (
dry ice),
carbon monoxide,
ammonia,
methane which make up such things as
comets and frozen
gas giants. Also, perhaps,
diamonds. As such, useful wording for
your local weather report in such places.
I have never heard the term
water snow used, however, nor the derived terms
water snowball or
water snowman. Perhaps these would serve as a welcome bit of local color if one were crafting a
space opera on the outer
planets.