Actually no. I rendered the particle snow with alpha channel to a tif sequence. Then I imported the video footage in After Effects, stabilized it, played around with the colors and finally added the snow on top of all.

What should be still done is to "track" the movement of the camera in maya so the snow would move according to the slight jitter of the real camera. Few mask objects on the major trees would add some realism too (so that the snow doesn't always show "through" the trees)...

Just playing around...