I'm inclined to agree with Earl. if you imagine the goose looking straight down you can see the pilot is twisted and bent in on the right side and the passenger section is bent on the frame in the opposite direction.
Judging from the picture , Rock meets Goose stopping the pilot and lead truck on the right side. Momentum wants to keep the goose going forward and the end result appears to be a jack-knifing effect and with the rock and or boulder in the way it then turned into a springboard and lifted the jack-knifing goose rolling it over on its side.
That would all be rather difficult to do in photo manipulation.
I really need to stop watching so much CSI.