Coincidentally, look what Neal Bortz had posted on his web site today:
Cool. I would lower it just a little more and put grass on the top though:')
LOL, I had envisioned them totally covered with dirt and wondered how you got to the door. I keep thinking about Helen Hunt's dad that gets sucked out with the door of the storm shelter in one of the movies. If the suck zone went right over that bus, would it rip the roof open or would that be a sufficient shelter?