"Oh my God - it's a waterfall!" Laughing on the edge of death

I might have posted this before - in fact, I probably HAVE posted this before - but if I want to see it again, I might as well see it here. This is a much better quality version from YouTube than the grainy, distorted thing going the rounds on Facebook. I know nothing about these guys or if there is more to the video than this, or, more importantly, WHO is shooting the video (which nobody thinks about). It seems impossible, unless some other vehicle is trailing them. Even more importantly, I want to know if they survived. But if they didn't, at least they went down laughing.