If you want to say "it is snowing" (as in right now, you can see it coming down), you will want to change the verb "huru" 降る(the imperfect or infinitive form) to it's progressive form "hutte iru" 降っている. (or hutte imasu 降っています, if the situation calls for it)
Otherwise, "yuki ga huru" 雪が降る generally just means "it snows".
One thing to keep in mind is that, in Japanese, nouns-type words do not change in to verbs as often as they do in English. What we see is that, while verb-type words may produce a noun, it usually does not happen the other way around.
Example: 出会う (deau, to encounter) -->出会い (deai, an encounter)
雪 (snow) -->雪が降る (it snows)