My father in law says that there are two reservoirs upriver of Swannanoa. After two days of heavy rain saturated the ground nearby, they were simultaneously let out on Friday, causing a flash flood through the valley.

I don’t have much access to maps to explain this fully, but it seems that the flooding wasn’t just from the hurricane, but there were man-made factors involved. https://video.nostr.build/8e592e86e047d45a1e5eb45aee35dff26338f8c3b13a7431c779a9fdeee568e9.mp4