This is the scary moment a kayaker in Austria got trapped in between and under rocks in whitewater rapids.<br /><br />In the video, filmed in October 2013, German kayaker Adrian Mattern, then 18, is paddling with a friend on a difficult Grade V run when he gets submerged underwater.<br /><br />"One small mistake lead to this very dangerous and close-call situation where I got trapped in between rocks underwater. Luckily the gap underwater was big enough to crawl my way through just to reappear. After another very dangerous rapid, I got luckily flushed down without major injuries. <br /><br />In the end, Mattern makes a swim to safety "alive but in shock." <br /><br />He writes: "Big lessons were learned that day. The river is boss, always."
