Can there be a rainbow when snow is falling; i.e., a 'snow bow'?
Yes...and unlike a rainbow...the sun doesn't have to be behind you and the rain in front of you. The geometry is different. Light snow or falling ice crystals and sunlight are needed...both in front of you. The exact effect depends upon the type of crystal and it's orientation as it falls. There are many amazing types of displays. Look at some of the types of ice crystal halos on this website www.atoptics.co.uk