it sounds like a freak accident but in an industry that is largely unregulated, it happens all too often. cnn's alina machado has more. >> reporter: this cell phone video shows a parasailing adventure gone horribly wrong. two teens slamming into a building and hit the top of another building before they come crashing down on the other side, stunned witnesses called for help. >> a parasail just smashed into the top of it at the commodore. >> they actually hit power lines in the front of the building. >> reporter: chase shot the horrific scene monday afternoon. sidney good and alexis fairchild are hospitalized with critical injuries. the teens were parasailing over the gulf of mexico when the winds kicked up from an approaching storm and their tow line snapped, sending them spiraling out of control. >> they were kicking their feet and they had their feet out,