I'm not sure what the product I used for snow is called (it's a German brand from a local hobby store) - I threw out the box when I transferred the stuff into a glass container, and hence can't recall the name.
Here's how I applied it though:
- First apply the standard coarse modelling sand onto the bases. This is to get patches of rock to show through the snow, and also to help the snow material stick to the base better. Remember to seal the sand onto the base with some watered-down PVA glue after the initial glueing.
- Once this is dry - basecoat in black, heavy drybrush in blue, then a light drybrush in white.
- Mix a solution of PVA glue, water, and snow material to a consistent density - not solid, but not so wet that it drips from your application brush.
- Apply the solution to the base where you want snow patches.
- Dunk the base into the pure snow material, to get an extra layer of snow on there.
- Leave to dry for about 6 hours.
- Shake off, blow off and brush off any snow that isn't glued down.
Here are some more shots from a higher angle so the basing is a bit clearer (click the photos to enlarge):