The bible story of Noah,s hydraulic lift to the top of Everest (beating E Hillary to it) is hilarious, and only makes sense, because no hill could have been left worldwide to hide on.
Jesus made the essential point that Armageddon will be similarly worldwide. No place to hide even under the mountains.
water vapor is lighter than air, so it was natural for the water to be up there. (like clouds). yeah, hot air. but 10 km of liquid water vaporized?
A 20 000 km shell of pre-flood water vapor ? falling in 40 days, 3 stories high each hour everywhere? floating the ice over greenland, antarctica?
Obviously, It is only in Einstein's time that the weiters / people of the book[s] become interested in exact science.