Many white particles can be used with thinned white glue. White flour, talcum powder, crushed and milled styrofoam, gypsum. Many hobby shops carry a white powder for snow.
The thinning ratio is important. I thin about four to one water:glue, and let it dry for a couple of minutes before dusting it on. There will be excess powder on top. Blow it off with mouth or fan afer 12 to 24 hours.