Hit a jump I've hit dozens of times already this season and went off wrong. For whatever reason I went off my heel edge and kind of slipped out on takeoff, and very, very slowly entered into an underflip.
It was one of those things where I was in the air and couldn't do anything to correct my positioning. I had time to think "man, this is going to hurt."
I dropped a good 20 feet straight to my butt/lower back. I was able to somewhat absorb the initial impact w/ my board but I took the brunt of it to the body. Head snapped back and cracked my head on the snow.
I was able to ride away from it but I'm now dealing with an intense bout of whiplash (my whole upper back/neck is very sore and it's hard to move my head back and forth).
I was wearing a helmet, but don't think I'd be typing this right now if I wasn't.
I guess I kind of get the folks who don't wear helmets when their freeriding, but if you're in the park, wear a helmet. There's no reason not too.