Yes! And as there has been these pictures of the snow gradually melting, I thought there might be a few more showing how the meadow gradually gets greener and greener, soon blossoming with flowers.

Your Finnish is grammatically correct and perfectly understandable. And in case you are interested in the nuances, I think in Finnish when we say "poissa" it has the connotation that you'd wish or expect something to be there but it is not. So "poissa" is something like missing, or absent. Referring to the snow I think we most commonly just say "sulanut" = melted. "Lumi on sulanut". But then it gets curiouser and curiouser =) As, for some reason the common idiom uses a plural form of snow. I'd guess the idea is something like "all of the snow". So, it would be "lumet ovat sulaneet", but in the spoken language we often say "lumet on sulannu" =)