I think that it could be make using spline-followed.
I have make some examples with different technics: following-spline, scale transformation (three from left to trees. It’s cool for 3D effects), and straight movement.
I figured out how to make it look like snow, But I can’t copy it in the sifz file of the scene I started. I don’t know if I can do the oposite by copying the scene in the particles file since my characters have all been linked to skeletons and I’ve never had success copying those from one file to another.
For the time being I’m exporting both seperately and putting them together in Kdenlive using a lighten transition between the files.
I finally got the snow working, you can check it out yourself. I had to put it together with the rest of the scene in Kdenlive because I couldn’t figure out how to import it with the particles working.