A simple way to create a snow material in V-Ray for 3ds max is to combine a VRayFastSSS2 material with a VRayFlakesMtl using a VRayBlendMtl.
The VRayFastSSS2 creates the soft translucent shading for the snow, and the VRayFlakesMtls adds sparkling highlights.
Note that depending on the scene and view scale,
The VRayFlakesMtls ‘flake glossiness’, ‘flake density’ and ‘flake size’ have to be tweaked to achieve the wanted result.
The shading normal‘s Z component can be easily used as a ready-to-use procedural mask for ‘covering effects’ like dust, snow, and if baked, also as a base for particle effects like debris and vegetation.
This simple shading flow example the shading normal‘s Z component, that represents how much the surface is facing upwards is separated , mixed (multiplied) with a noise textured and than fed into a ColorRampConverter node for fine tuning the resulting mask:
This is the full shading flow of the snow effect in the image above: