Another possibility (Score 1)

Okay, I don't have my Bible near me, so this will be from memory...But I remember that the Israelites waited by the Sea of Reeds or the Red Sea or whatever it was for a couple nights...I think 3...while Moses 'communed with God' or whatever it is he does. Probably, what he was doing was just checking out the rise and fall of the tides, so that the Israelites all crossed while it was safe, but the Egyptians hit it at high tide. And even more likely than that is that the Egyptians weren't actually killed off by the rising tides, but just got so bogged down in the water that they decided that it wasn't worth it and just turned back...but how could the Israelites know? They just knew that the water rose and the Egyptians didn't come after them anymore...so therefore, they must have been wiped out by their powerful god YHWH.