Your 'choppy day' is cute. Compared to this!

"When the flow is up, that's when you've got to be there. That's when we drop everything and go."

"Flows's Up Dude" doesn't really have the same ring to it as the traditional 'Surf's Up', but you know what? These guys and girls are Stand up paddling at a whole other level.

They're whitewater paddlers, and if you think your last paddle was a bit choppy. Think again. If you still need convincing, how about watching one guy go hurtling down a chocolate brown river that it absolutely churning itself downstream. That takes some serious skill - and a solid board.

Whitewater paddling isn't huge here in Australia, because there's not many places you can do it. Over in the US, it's going bananas at the typical kayak/rafting locations, with whole businesses being set up dedicated to the boards and gear. Speaking of boards, this whole discipline of the sport would not have been possible without the advances in inflatable board production. Epoxy stand up paddle boards wouldn't last one run down the river without cracking, scratching or snapping in half; yet an inflatable can be run through the rocks, stabbed with a paddle and it can even smack you in the face with little in the way of consequences. Except your face. That's in the way…

Watch these whitewater SUP paddlers going nuts in some incredible conditions, because after all - when the 'flow's up', you drop everything and go!