Victim was tubing on lake Greeson with his family.  Operator was pulling 2 tubes; victim was on 1 tube and 2 other occupants were on the other tube.  They were in the area between Kirby Landing and Bear Creek.  Operator estimated they were going 18 to 20 mph when he began turning to the left; the tubes were "sling-shot" across and outside V1's wake.  The observer on V1 noticed the victim lying face down in the water and not moving.  She called for one of the other tube's occupants to "go get him"; which he did and turned the victim upright.  Victim was knocked unconscious and bleeding severely from his face.  They called 911 and headed to Kirby Landing where they met the ambulance.  
 
Upon interview of the victim at the hospital; he was still groggy from the pain medicine but he stated just as he exited the wake something black hit him in the face and knocked him out of the tube and that was the last thing he remembered.
 
Due to heavy rains recently over the last several days, there was a lot of debris in the lake and this is likely what hit the victim.
KIRBY