Why Can't We Get a Handle on This Safety Thing 3

You top-land at Marshall half crosswind, gliding up the backside of the hill. You come in hot, because the gradient can be extreme, and there's often some degree of turbulence. The time interval from 40 mph dive, through round-out, to flare is very short. I was halfway through this interval, past the point where one is normally rocked by whatever turbulence is present, when both my left wing and the nose dropped suddenly and severely. I went immediately to full-opposite roll control, and managed to get the wings and nose just level when the basetube hit. Having turned 90 degrees, I was traveling mostly downwind, at a ground speed of probably 30 mph. The right downtube collapsed immediately, and the right side of my face and body hit the ground hard.
Very briefly I thought I might die. For a slightly longer time I thought about paralysis. Within a minute, I knew I was mostly okay. In the end, I got away with a slightly sprained ankle and a moderate case of whiplash. I had three weeks to think about the accident while I bounced around the rutted dirt roads of East Africa trying in vain to keep my head balanced directly over my spine to moderate the pain.
The thing was, I never considered at the time of the landing that I was anywhere near "pushing the envelope." I've done dozens of landings at Marshall during which I did feel that way. All during the previous two summers I had been top-landing RamAirs at Marshall in the middle of the day in much stronger conditions. I had never had a crash. Thinking about it, I couldn't even remember the last time I had broken a downtube. I tried in vain to think of a clue I had missed that this was going to be a dangerous landing.