Bill said "How could that be when considering a fairly sudden happening? Even the end of an ice age and melting of glaciers would take many years and only raise total sea level a couple of feet." It could be successfully argued, and this based on geological study, that such an increase could easily have caused a build up of pressure and weakening of land structure between two bodies of water of differing volume, or between a large body of water and a large basin, so that the natural dam structure might breach and cause a massive flooding of the adjacent area.
Additionally, the great cataclysm that destroyed most of the Mycenean culture in ancient times, probably a huge event of volcanic origin, caused massive flooding throughout the Mediterranean, and is used by believers in the existance and destruction of Atlantis as a possible cause.
Such events, although extremely rare, could easily have embedded themselves in the oral history of many cultures, and become embroidered with unlikely detail and principle players over the thousands of years since their occurence.
So, I believe Little Hawk is right in saying there may very well have been a great flood event that is the root of the ark story. The balance of the story, with Ararat, animals by twos, God's blueprint for the ark, was invented as a means of explaining that event, and using it to support the storyteller's agenda. In that way, nothing has really changed, has it?