I think this is lovely, and it looks soooo cold! :-)

The only recommendation I can think of is that the solid snowflakes close to the camera have a matte material, and I tend to think of snowflakes as icy-transparent. You could re-texture them and just plop-render those areas, to avoid a long re-render of the whole scene.

Two other questions:

1. What are those stick things on the ice in the foreground?
2. The terrain in the middle on the right, it sort of looks like we're seeing under it. Is that my imagination?