The biggest hurdle I've seen with either the Glacial Flood or the Black Sea flood has been speed and that they would be coastal events. There were many such events and folk at the coasts would also be familar with storm surge and even things like the tsunami.
I believe that if you're going to find the source of the Flood Myth you will do better if you look to riverine/plains systems. If you look at the wide plains between the Tigris and Euphrates you might do well. Since it's likely that most of the content of Genesis was formed during the exile in that area, it would be reasonable to look for the source in the history and mythology from that area.
Have you looked there?
Aslan is not a Tame Lion