It's probably more than 90% 2T's because 4$ is a b*tch to start hot or cold. Considering how they have to start the bike, then race it, it's probably better timing and quicker to get ahead. Not to mention the power to weight ratio is pretty crucial and the 2T is obviously the optimum bike in the field.
As far as as snow goes, you guys must be spoiled with your warm climates
Bring on the snow. Just kidding, that looked hard enough as it was, but imagine if the snow actually had accumulated?