I remember a video from Andrew Price aka "Blender Guru" about creating snow in Blender. He used a "Voronoi Texture" for mimicking the reflections and refractions of the countless microscopic ice crystals. So, I've choosen this setup with the "EEVEE Material Preview":
For demonstration purposes with a lower scale of the "Voronoi Texture" which I also connected to a "Viewer Node":
Oh those look pretty cool, very minuscule/crystalline detail! -Chunck :)