Here is a link to some screenshots of the scene setup. Including the material node tree for the snow, I hope this answers your question! xDsta.sh/2g8wx594l78?edit=1
The snow is essentially just a triangulated plane, with a displacement modifier on it, making it look like hills etc. The material is just a single diffuse node with two colors of white mixed together with a noise texture as the factor. What gives the snow its look is just a noise texture being used as a displacement map on the material output node.