Mask Problem?

my first post :slight_smile:

Trying to create a mask using the fla files covered in the Flash tutorial called Falling Snow

I want to mask cetain areas of the snow, but the snow dont want to mask

it seems the snow is always on top no matter where i position the layer or any graphics i try to over lay on top of it? Does this have to do with the movie clip duplicating??

any help would be great!!!