Originally Posted by
cyccommute
I don't see how "cutting throughs the snow to pavement" helps any. First, as your picture shows, you are shoving snow out of the way with the tire, rim and spokes. Shoving anything out of the way takes more power. Secondly, the tire doesn't "cut" anything. It compresses it. The smaller profile of the contact patch might even be enough to make it liquid which makes the tire/ice interface even slicker.
The snow layer on both sides of the wheel actually adds substantially to the lateral traction so the slickness of the tire/ice interface is of little importance. It is lots of fun to do controlled slides and donuts on a frozen lake with 4-6 inches of snow on it - something that is pretty much impossible on bare, slick ice.