Simple math.
It rained for 40 days and 40 nights. (Or was that "Prophetic Hyperbole"?).
There are roughly 60,000 minutes in a 40 day period. The rain covered the highest mountain in the world which is roughly 30,000 feet above sea level. That would mean that the rain fell at a constant rate of 6 inches per minute. I doubt anyone could survive even 5 minutes of that kind of downpour.
It should be obvious to anyone who interprets Scripture in light of Scripture that Jesus was using prophetic hyperbole.
If Jesus used "prophetic hyperbole" then why should we believe anything Jesus said? How do we know he wasn't using hyperbole when he said that we would be granted "eternal life"? How do you know that he wasn't using Hyperbole when he said he would be with us forever?
If Christ foretold the future by exaggerating it, then he was a False Prophet. You can't get around that. The Jews would have been justified in stoning him.
the highest mountain in the world which is roughly 30,000 feet above sea level.
That is the case in this era. Was it the case in the world that then was?