I just saw this video on reddit. It's only a shallow ditch, so only dangerous to bugs and lizards probably, but it reminded me of the times that LL mentioned flooding in various stories. It's not even raining where the camera is, but the water comes through the ditch pushing a lot of small logs and limbs at the front. It's a miniature version of what he talked about in his stories, and you can see how it could be dangerous in a larger gully.
Takes a while to get going, so you can skip the first 40 seconds or so.
https://www.reddit.com/r/Damnthatsinteresting/comments/p47txf/crazy_desert_flash_flood/?utm_medium=android_app&utm_source=share

Peter