At least Ninevah got a warning!!
Genesis 6:11-13
11 Now the earth was corrupt in God’s sight and was full of violence. 12 God saw how corrupt the earth had become, for all the people on earth had corrupted their ways. 13 So God said to Noah, “I am going to put an end to all people, for the earth is filled with violence because of them. I am surely going to destroy both them and the earth.
Dontcka think Noah’s neighbors had a warning? He could not have built that Ark in a month, and surely they asked him, but ridiculed him for telling them God was going to send a flood upon the Earth. It’s kinda sorta like now, when warning that the Rapture is coming very soon. The ridicule factor is impossible to miss, but the message has to be given anyway.