Houdini's greatest selling point as a 3D app is its procedural workflow. I wanted to create a tool that could place snow geo on environments without having to model the snow. You could just build out your environment without snow and then use this tool to generate the snow on top of everything. I spent a morning with it and came up with a rough beginning. The basics are in there but it could be refined a bit:
You'll notice that which ever way the torus is rotated the snow stays on top. As is, the snow isn't shaded yet. I know that I could do all of the snow in displacement and I may yet play with that a little more as I work with it.