Such speculation got me thinking about Noah's flood, and the possibility that a massive asteroid impact put the vapor in the air, the shock wave broke up "the fountains of the deep", and the earth was knocked off its axis, and "seedtime and harvest, and cold and heat, and summer and winter" -- the seasons -- began.
This fits with what i believe as far as God's way of creating the flood.....(i believe that he used natural forces to create the flood and other things to inspire discussions just like this one, so that in the end it comes down to FAITH!!).
Before the "flood" there was no rain as we know it today according to the bible.....couple that with an ice age that science tells us ended approx. 10,000 - 7500 years ago with MANY more times the amount of ice at the poles extending much further outward into todays warmer climates....throw in your scenerio and walla.....you might have enough water to cover the earth!!!
With that said.....it may just be that God blinked and there was a world wide flood.....it ultimately comes down to FAITH!!!