A fire can still burn in a snowy environment if the snow has actually stopped coming down. An excellent example is a zombie wildfire, named so because it doesn’t go out even in the arctic or wintertime. Basically, the fire starts underground and slowly grows out, and when winter arrives, the fire is already so rooted that the cold doesn’t put it out, instead feeding it so the fire continues ravaging across the arctic. They form underground by ice and snow melting into heavy layers of peat and straw that creates heavy insulation that is easy to ignite in hot or humid environments.