It was just so close to the car in front that it was running very slow air (relative to the car). Without the downforce from the body cresting the hill at that speed probably got eh car close to weightless and the faster air above the car sucked it up. The rest is down to Newton.
I don't think the aerodynamics were out for an open track, but you'd think they'd take slipstreaming into account too!
The idea of drafting is to use the car in front as a drag barrier. The problem with this is that the drag is beneficial for keeping the car on the ground. Without the higher pressure above and maintaining the same pressure below the vehicle, it's lift off time.
http://www.videosift.com/video/Horrifying-Sports-Car-Somersault
I don't think the aerodynamics were out for an open track, but you'd think they'd take slipstreaming into account too!
Good for aviation, bad for race car driving.