So I thought i'd try to take a stab at this.
No bitmap textures. All noise and displacement from C4D/Octane. Its unfortunately very slow to render (this frame was about 4min.), but I think its fairly close to actual snow. I've included my project file for others to mess with. If you get a better result in a faster render time, please post it for us to see!
I have a mix material with a base snow texture made up from a specular material with absorbtion medium, transmission, and a very high roughness, and a specular material for the snow's spec with a voronoi noise in the specular channel. The mix material has a noise displacement.
Here's my result: