The pool, and all those sitting next to it, were instantly frozen solid by the Alien craft that has been shooting a freezing death-ray indiscriminately around the world. Google "Aliens freezing" and "Aliens attack Grand Canyon", and you will see that there is a world-wide conspiracy to keep this news from reaching the public.
Uh, oh, there is somebody pounding on my front door!!! I HOPE IT'S NOT THEM!!!