The abrupt release of water and the resultant rise of the sea level was very quick. The rise is estimated to be 45 feet. That is a bit too precise. It could just as easily been twice as large. It was also followed by a slower and steady rise as the balance of the ice melted out. The main event certainly played out in weeks, however.
It certainly explains one anomalous feature of the legend rather nicely. Noah built a boat; it floated for forty days and then was grounded. A rising sea that was slowly driving inland on a plain or delta would most likely give this experience. This is not true for a normal river flood.
Maybe Noah was the local mathematician - scholar who got word that the great ice dam was ready to break and did the basic calculations and acted on them.
It also explains the global distribution of this flood motif. Everybody was affected who had access to a coast. This is another important point. The majority of the global population has always been concentrated on the coast and often exploiting the sea itself. Remember the Pacific Northwest were huge Stone Age populations built up based on seafood. The inland was difficult and only modestly used and could never support any real population even today. Nice to look at though.
We also know that prior to the climate stabilizing, that the temperate interior was only suitable for small hunter gatherer bands with an attendant low population. They would have penetrated every valley on Earth but they lived a circumscribed life way. At best, they had begun cattle husbandry which really lends itself to that type of small band society.
Another direct result of a rapid rise of the sea would be the actual destruction of a large portion of the coastal population, if only through a loss of their livelihoods. Shell beds would be lost for a generation and this was a major staple as the fisheries were very seasonal. This means that the repopulation of the coasts would have come from the inland and highland populations conforming to the archeological and other evidence.
We could now run amok and make all sorts of other suggestions. However a real global coastal flood confirms the one salient global fact. There was a global flood. There were also eye witnesses who were seriously impressed. We now know when it happened. The rest of the legend can be safely dismissed as embroidery. Great story though.
Some of this embroidery could also be material folded in from unrelated events such as forty days of rain. That is not impossible by itself in the aftermath of a volcano perhaps. The tale of the dove is so clearly part and parcel of the religious symbolic tool kit as need no further comment.
During the four to six thousand years that it took to melt the northern Ice Cap, the sea was always persistently rising by on average about half an inch per year. This is barely faster than geological motion and totally unnoticeable. Thus the only event that could ever have been noticed was the release of Lake Agassiz into the Atlantic Ocean. It is right to call it Noah’s Flood.