Many Christians today believe that Genesis is open for interpretation. The flood, for example, could easily have been local. Thankfully, Noah didn't think like that. If he had, God's command to build an ark would seem strange to him.
Noah: You're telling me I have to build a 450ft boat when I could just as easily migrate a few miles?
God: no, Noah, listen again: The end of all flesh has come before Me, for the earth is filled with violence through them; and behold, I will destroy them with the earth. (Genesis 6:13). Now go and make that ark!
Noah: But God, surely if you're sending a local flood, it'll be easier to just get to high ground. That's what any sane person would do during a local flood.
God: How are you not understanding what I'm saying? I am bringing floodwaters on the earth, to destroy from under heaven all flesh in which is the breath of life; everything that is on the earth shall die. (Genesis 6:17). That includes you and your family if you don't get on that ark.
Noah: I'll just climb the high mountain until the flood passes. It's easier to move away from the local flood than to cut down all those trees.
God: No, listen, Noah, the waters will prevail fifteen cubits upward, and the mountains will be covered. (Genesis 7:20). All flesh will die that moves on the earth: birds and cattle and beasts and every creeping thing that creeps on the earth, and every man. (Genesis 7:21). Get. On. That. Ark.
Noah: Can't I just move to Israel?
God: This is why my Son has to die for these silly creatures 😒
From the Scriptures, it's pretty obvious that the flood of Noah's day was global. It is Biblically impossible to argue for a local flood. The only two consistent options are to either completely reject the Bible, or accept a global flood. Christians, take your pick. God's word, or total insanity?