If the rain didn't come from the waters above the firmament, then where did they come from?
Thank you, dear brother, Romans34! It's always excellent to speak to a brother who is straight forward as opposed to deflecting and one who is reasonable.
Your question is the obvious question. Together we have scripture and all that the Lord gave us to understand it. Scripture reads:
Gen 7:11 In the six hundredth year of Noah's life, in the second month, the seventeenth day of the month, the same day were
all the fountains of the great deep broken up, and the windows of heaven were opened.
This is one of the many fold reasons I have confidence in scripture: "all the fountains of the great deep broken up". It also did rain, but it seems logical that's a function of distribution, not source. There are two reasons why there's enough water on the earth to flood it.
People have known there's water under the surface of the earth since the digging of wells. Knowledge, techniques and technology has increased through the ages and discoveries of vast amounts water under the earth continues. In a recent 2023 Scientific America article, after finding a vast deposit of fresh water under the ocean floor off the coast using CSEM (controlled source electromagnetic) they estimated there's "
one million cubic kilometers" of fresh water just off the coasts worldwide. That's just the coasts.
How much water is under the earth, here on the water planet? We surely don't know. Not only could "all the fountains of the great deep broken up" be more than enough to have covered the surface of the earth way back at the time of the Flood, but in addition to that, the surface of the ocean deep could be pushed up to "sea level", displacing all ocean water across the surface.
There's all that... and there's the fact that our God is all-powerful and capable of miracles. The text does not read the Flood waters came from the waters above the firmament, which scripture reads has been separated from the waters below it, but it does read it came from "all the fountains of the great deep". Genesis uses the term heavens as the abode of birds and rain. I don't see any scriptural or logical reason to suggest it came from the waters above the firmament.