if you re-read my post,we already have reservations for Yellowstone at Madison Campground.We have researched the weather and know it can snow but have all wheel drive and chains. We've been told by others that at that time of year,if you get snow one day,the next day the roads will be plowed.We weren't aware that the south entrance won't open until 2 days after our arrival.I guess we will change our route.My question about reservation were about the other campgrounds I mentioned along the route for that time of year.