Well, being the Prius is not a high torque vehicle I would expect it not to be too good in snow driving. Sure, the mileage will suffer some, but it is better than having to get towed out of a ditch! Prius also don't do well in very highly mountainous areas in terms of mileage for the same reasons. My buddy has one in CO and his mileage is nowhere near what I get in flat FL.