Charles Ellicott Commentary Genesis 7:24

"And the waters prevailed upon the earth a hundred and fifty days." — Genesis 7:24 (ASV)

prevailed. —Hebrew, were strong, as in Genesis 7:18. The rains lasted forty days; for one hundred and ten more days they still bore up the ark, and then it grounded. But though still mighty, they had by this time “abated” , since, instead of covering the hills to the depth of nearly four fathoms, the ark now had touched dry land. Again, then, the narrative seems to give the personal experiences of someone in the ark.