Snow has a tendency to build up on windscreens and leading edges, restricting visibility and changing aerofoil shape.
Gen the Eng . . . . . . I think you're referring to ice ! According to the latest copy the the US 'Flying' magazine which happens to have an article on this very subject, they say that there is no problem flying in snow (providing it's not the wet/sleety variety that could turn to ice).
So, according to them, light to medium dry powdery snow just blows straight across the airframe without any problem.
If it gets very heavy then it can clog air intakes . . . . . . . . but at least you will have a soft landing
