Once things get in motion it can go very quickly. It must have looked like this: https://www.youtube.com/watch?v=eDmoXkF-g9I https://www.youtube.com/watch?v=eDm

Once things get in motion it can go very quickly. It must have looked like this: https://www.youtube.com/watch?v=eDmoXkF-g9I https://www.youtube.com/watch?v=eDmoXkF-g9I Starting very small and then growing exponentially. When I was a child we also did something like in the video. The initial channel was very narrow and we could have easily stopped it by putting back some sand, but 15 minutes later through the game of erosion the stream was so intense that it became impossible to even cross it.