RedactedNarrative: Vessel 1 was cruising northbound on Lake Powell, north of the north edge of the wakeless area at Anchovy Point.  Vessel 1 was operating at an estimated 5 mph or less due to choppy waves and wind.  Vessel 2 was cruising southbound and passed Vessel 1 on the port side.  The occupants of Vessel 1 estimated Vessel 2 passed 50-60 feet to the side of their vessel.  The operatior of Vessel 1 stated he kept "...a good distance from them."  
  
  Vessel 2''s wake caused Vessel 1 to go up and down in an abrupt and notable fashion.  This upward/downward motion caused subject who was seated in Vessel 1, to be tossed upward, losing contact with her seat.  She then came down and struck her seat with her posterior in a sharp manner.  This impact caused injury to her lower back.  She was subsequently transported to the Page Hospital where she was evaluated and determined to have fractured a verterbrae.