For snow on vehicles I use hairspray ( semi gloss ) and artificial snow. Woodland Scenic
I took 1/ 4 of the snow , mixed it with glue , spread flat. dried and then broken so I have chunks of snow and ice. Some of these are tinted blue and green with wash.( Oil)
I mask off an area ( example wheel ) spray hair spray and dump on the artificial snow..wait..lightly tap off excess and viola a light puffy snow ball. Held together by hairspray and static electricity.
For packed on stuff I use white puddy, wash it light blue/ green( oil paint ) add chunks of artificial snow or any debris and then top with layers of artificial snow. Adding rocks, grass, mud stains, twig as I go.
For tank dusting ( or wind accumalation ) I use a custom Solveset mix in airbrush with a fan.
The only problem with this is that you can't spray sealer on any of it. So It would be last step stuff like road dusting. Sealer will turn it grey and icy. You can't even touch due to oils on your fingers. Shouldn't be touching anyway...extremely delicate step in a build is snow.
The reason I say paint the packed stuff with a light blue wash and then top. The blue/green gives it depth and shine and the snow doesn't get lost in the shadows and just looking like white mud or something. You won't even really see the blue or green...it will be just a glow.
This method is great for snow banks.
And keep it semi glossy ( hence the hairspray..not to mention it's long working time, it bubbles creating texture and general stickiness ) snow is wet and shiny.
I was also able to puff up the artificial snow even more by putting it into a paint mixer.
Good luck and happy snowing. Show pics. I wish I could but I don't have snow ones here