And God made a wind blow over the earth, and the waters subsided (Gen 8:1).
1. On the face of it, this explanation is a headscratcher. How could wind cause the flood waters to abate? If anything, this is more puzzling on the global-flood interpretation. If the spherical earth was submerged in water, wind would simply generate continuous wave action.
Flood geologists like Kurt Wise (Faith, Form, and Time), Andrew Snelling (Earth's Catastrophic Past), and Jonathan Sarfati (The Genesis Account), invoke catastrophic plate tectonics as the real mechanism causing the flood waters to subside. But on that view, the wind has no effect on the flood. So that substitutes an entirely different explanation. On that view, the wind has no explanatory value at all. It does no meaningful work. If, however, the text attributes the abatement of the flood waters to the wind, then we should seek an interpretation which takes that seriously. At the very least, that should be a primary cause.
2. One possible alternative is that it doesn't mean "wind" but "Spirit". Commentators are quick to say 8:1 echoes 1:2. If 8:1 refers to the Spirit of God, then it might mean God miraculously caused the floodwaters to abate. There are, however, some difficulties with that identification:
i) In Gen 1:2, you have a title: "the ruach of God". Gen 8:1 doesn't use that title. So I don't assume these have equivalent referents.
ii) If it was a miracle, it's odd that it still took months for the flood waters to subside.
iii) Since Gen 7:11 cites natural mechanisms as the source of the floodwaters, we might expect, by parity, that the source of their abatement to be a natural mechanism as well.
iv) This isn't the only place in the Pentateuch where God sends wind to perform a providential task. As one commentator notes:
Moses witnessed the might of God's "wind" to induce and chase away a locust plague (Exod 10:13,19) and deliver his people from Egyptian armies at the sea on "dry ground" (Exod 14:21; 15:10). It was with the same "wind" that the Lord provided cal for the vagabond people of the desert (Num 11:31). K. Mathews, Genesis 1:11:26, 384-85.
That suggests a preternatural force. It isn't strictly natural or supernatural. Rather, it's a natural force that's supernaturally directed.
3. Yet that leaves unanswered the question of how wind could make the floodwaters recede. The answer depends on how we visualize the flood. Consider a local-flood interpretation: Among other things, rivers serve as drainage mechanisms. In case of torrential rain, they become swollen. As a result, river basis are flood basins.
However, this can be magnified by the further fact that torrential rain causes debris to flow downstream. Debris can dam a river when it forms a logjam. That, in turn, causes water to back up, thereby expanding the inundated area upstream.
It doesn't take much imagination to visualize how a strong wind like a tornado or waterspout could disrupt a logjam, thereby releasing the pent-up waters. If it broke it up entirely, the runoff would be explosive. If it weakened the logjam, it might cause the natural dam to leak. In that event the runoff would be more gradual.
4. It might be objected that my explanation is speculative. No doubt. However, postulates involving hydroplate theory or catastrophic plate tectonics are speculative. Moreover, my explanation is an extension of the text, whereas attributing the recession of the flood waters to tectonic and seismic activity has no connection to the text, and sets aside what the text says.
If we wish to understand the flood as a real event, then we need to go beyond the text to visualize a more specific scenario, extrapolating from the text to a more detailed reconstruction. That has the limitations of any conjectural reconstruction. My explanation at least has a toehold in the text, by developing explanation that's given in the text–rather than replacing that with something wholly extraneous to the text.