As mentioned, nobody knew this was coming - in fact, the news told people in the areas which would be hardest-hit (East TN & West NC) that there would be very few issues (see photo 3).
There are many cases where people were filming minor flooding in the morning, poasting it to social media, & then by the evening their home would be washed-away.
The last major flood before Helene in this part of the country was The Great Flood of 1916 (see photo 4).
The Great Flood of 1916 wasn't even one storm either, but rather it was two hurricanes which hit back-to-back, creating enough rain to raise the French Broad River up 21ft in Asheville.
In Asheville, Helene caused flooding over 24.5ft
It is a criminal understatement to say that this area was "unprepared"; for the folks living here, the idea that something like this might happen was inconcevable... but it happened.. & worse: the government (Federal & the State of NC) worked to make sure that the area would remain damaged for as long as possible.