Vessel was in whitewater rapid, Howards Plunge, when the victim was thrown out of the vessel.  When this occured, the victim struck a rock with his back and head.  The vessel passed over the victim and he grabbed on to it until the victim could get to a rock.  The victim was then picked up by another vessel and taken to shore.  EMS responded, treated,  and transported the victim to the hospital for his injuries.  Operator report is partial.
Smiths Ferry                  