"Who was there to remember this flood that killed every human except the ones in Noah's ark?"
The decendants of Noah and his children.
There are so many basic "facts" about the story that just don't make sense--one couldn't fit all of the supposeldy surviving animals on a ship 450 feet long; how animals somehow got across oceans to get to the ark or be retrieved for passage on the ark; how EVERY animal that crawled on the land--including insects, reptiles, etc.--was somehow gathered and loaded on in the time specified; where'd the food for all these animals come from, again, on an ark of that size; how did Noah and his family handle taking care of that many animals for 40 days; considering how confident everyone here is about the impossibility of the planet Earth changing due to global warming in the course of hundreds of years (at minimum), we're supposed to just believe ALL of the planet was covered in water and then receded in 40 days? etc. etc. etc....
Religious faith is about faith, so whenever folks try to convince me of the "factual" basis of these things, they've lost already, by definition.
The decendants of Noah and his children.
In southern Alaska there is a cave, from which an individual was recovered. He was dated over 10,000 years old.
mtDNA shows some of his descendants can still be found on the west coasts of North and South America, and a few places elsewhere.
How do you explain that? No replacement by Noah's mtDNA.
And this is only one of the findings of archaeology in the western US that disputes the notion of a global flood at the generally appointed date ca. 2300 BC.