but you have the temperature for it (and you have a power washer).
Short version, you combine a power washer and an air compressor, let that mofo fly in a cold back yard and enjoy! (click the source link for the actual instructions).
Clickable link -> http://youtu.be/xuviX086dPs
Source -> http://www.instructables.com/id/Home-Snowmaker-Snowgun-internal-mix/ via lifehacker