"We were over the savannah and looking at the front of this cloud coming at us. We were perhaps 3,000ft above the Earth, but it felt like nothing. We turned the engine off and we flew in silence towards this thing, and I felt like a shrimp being sucked into the lips of a whale. We were going down and down, and then suddenly we were going up. We got the lift and turned left and surfed along the face of that wave. That was the most exciting thing I"ve ever done in a glider. We did seven waves."