At some point, I saw some PBS special or read some article or something (I can't remember) that proposed that the area where the "Red Sea" was had earthquake activity and that is what caused the "parting," which was a temporary result of an earthquake which allowed some folks across and not others. I have no idea how plausible that is or anything. It was not from a Christian source that I heard it from, I do remember that, but considering they didn't know exactly where it occurred or anything I think it is a hypothesis that is, at best, possible but unlikely.
As for the flood, there are lots and lots of myths around the world of a giant flood. I'm of the camp that thinks there probably was some big flood, but not exactly how the Bible describes it or for those reasons (i.e., I don't buy the firmament idea). One good scientific possibility was that a comet hit the earth around then off the East coast of Africa and caused some really huge tsunamis, followed by torrential rains from throwing up a lot of seawater into the atmosphere. Considering the number of myths from all over Africa, Middle East, Asia, Europe, Americas- pretty much all over- that all congeal around the same broad swath of time, it's fairly plausible that there was some sort of big event. However, I just can't buy that only Noah and his family made it out alive, or that he fit all the species of the world into a boat (I mean, how'd he get the American and Australian ones in there?).
I tend to think myth is typically based loosely on real events, combined with deep spiritual meaning. The real important part is in the meaning, so I'm not a real seeker when it comes to "how" and "did it really" and all the details. At the same time, some myths that seemed impossible (or at least highly unlikely) have solid evidence of some foundation to them at this point, and science itself has gotten so weird with quantum mechanics and string theory, that I don't discount them wholesale either.
