Having driven in both snow and ice, I must say that I would take Chigago's 6-10 inches of snow over 0.1 inches of ice any day. Snow is predictable and offers significantly more traction than ice. Even at <5 mph on ice you can easily end up facing in a direction completely opposite your intended one. Give me snow any day. I remember one day I went out after a freezing rain storm and my car was literally frozen to the driveway. It wasn't anything that couldn't easily be broken out of, but it was interesting. That same storm also froze my doors shut, had to chip the ice away with my keys.
Zenmervolt