Flash floods can form out of sight. You might not have rain where you are, but the water is coming downstream. https://www.youtube.com/watch?v=8p2vzhTMhW0 http

Flash floods can form out of sight. You might not have rain where you are, but the water is coming downstream. https://www.youtube.com/watch?v=8p2vzhTMhW0 https://www.youtube.com/watch?v=8p2vzhTMhW0 Now imagine you are in a gorge or choke point where it narrows suddenly.