Thank you for pointing that out Otto.
I am surprised there are so few categories for example severe turbulence goes from Wingo's "The aircraft by be out of control for short periods accompanied by large variations in airspeed. Occupants are forced violently against seat belts. Loose objects are tossed around." to actual aircraft break up. The Boeing 777 wing load test
YouTube - Boeing 777 Wing Load Test is interesting. One would imagine they would have failed much earlier with lesser forces outside such a controlled laboratory environment.