I don't think snow brings the same risks as structural icing i.e. flight through supercooled water with the TAT being below 0C.
Snow is frozen to start with.
Snow can certainly accumulate and is thus dangerous, but would it accumulate without limit, the way ice can do? I don't know. On the rare occassions I have flown through falling snow it did not seem to be sticking at all.
My guess is that the really dangerous thing is higher up; snow is often (always?) formed when freezing rain falls into colder air, and you definitely do not want to be flying in freezing rain. One meteorologist told me that snow is always formed from freezing rain but I am no sure about this.
Last edited by IO540; 2nd Feb 2009 at 12:19.