Not too long ago a video for carnage of the year surfaced where a guy tried a reverse free wheel, and ended up getting stuffed behind the curtain of the falls for about 5 minutes!
This video ended up on reddit.com/r/whitewater, a small community of boaters, mostly from the south-east I think.
Turns out the guy in the video also visits that website, and he wrote a detailed explanation of the event. It's the top comment on the page.
Crazy Beatdown : whitewater
Here's the video for those who haven't seen it.