When you water ski, you have something pulling you to stay afloat. I'm just surprised he carried enough speed to turn and not lose all his momentum and sink is all.
you can skim the blue river in breck at the base of peak 9. i've done it a few times. its pretty fun. best time for it is the end of a spring day when the slush is freezing again. any other time you won't get enough speed to cross it or it'll be frozen.