The cliche would have it that you couldn't make this stuff up, but of course you could. But people wouldn't believe you.
"...recently found evidence that rain-making bacteria are widely distributed in the atmosphere...This is important because the formation of ice in clouds is required for snow and most rainfall. Dust and soot particles can serve as ice nuclei, but biological ice nuclei are capable of catalyzing freezing at much warmer temperatures."
So, maybe bugs make snow. Cool. Full article here.