Good point. So the dramatic thaw = flood myth? And that legend survived memory transmission down through the ages?
I know that just about every culture seems to have legends of a huge flood, but I don't know if they're memories of the same flood, or that bad floods are pretty common and these memories/legends are just local events for each culture.
If there was some global event that occurred that was capable of raising temperatures rapidly enough to melt glacial ice around the world and cause catastrophic flooding then surviving the flood would probably have been the least of the survivors' concerns.