Umm, but there is a lot of evidence. Sediment layers, glacial ice cores, lots of evidence. It is surprising what people will accept from science on one hand, and reject in the other.
Yeah like ignoring megalithic structures all across the globe which have suddenly been destroyed by a global catastrophic event around 6-8000 years ago.
I am assuming you are talking about the biblical flood? You are using their lines. So he issue is the flood of the bible lasted 40 days, and these events spread thousands of years.