. >> reporter: mac and kiley mackinnon grew up together. same first grade class.h were natural athletes. kyrie mastering a bike at three. >> look at her go, daddy. >> reporter: mac flipping on the backyard trampoline. both families loved to ski. >> nice, guys. >> all right, mackie! >> reporter: before long mac started flipping on the slopes. >> oh, yeah, big mac. >> reporter: that's when he called kiley. >> he's like, you know what? we need more females in the sport of aerials. i think you should try it. you're a gymnast, a skier, perfect fit. >> reporter: they invited us to watch. mac announced he had a new trick up his sleeve. >> i planned on doing one variation. full triple full full, which is called the hurricane. >> i didn't know about this. >> reporter: you're shaking your head. >> that's awesome. >> reporter: a missed hurricane is less painful in the water if only slightly. you might be looking at this and thinking, wow, that must be fun, water slide, jump into the pool. then you climb up here five stories and you look down that ramp and realize, oh, my. th