The ops group I work in had our yearly rafting trip on the Yuba river. It had a few class 4s and one class 5 which was optional for participants. One of the 4 rafts did get sucked by a backwash and ended up upside down with everyone swiming for their lives (more or less) especially as the rapids were followed by another class 4 soon afterwards. Some swam to shore and 3 others made it on top of the flipped over raft and rode the class 4 that way :)
Anyway, a lot of people saw water but my raft was fine and we all had a great time :)



All the pictures are here