Somewhat more noise in the foreground terrain might have made the show more real. The background terrain works more like real snow. Partly also because it is more blue, while the foreground looks like slightly purplish.
It is not so much adding noise to the materials, but to the terrain itself. If you have e.g. rolling hills, you can click on 'basic noise' or probably 'height noise' works better. Of course, you have to find the deep terrain editor (DTE) first! You can indeed also add all kinds of noise to materials. You then have to go into the material editor. Look for 'David Brinnen' tutorials, he shows all anybody knows about materials in Bryce.