Why coastal floods have little to do with rain and everything to do with wind. Most of the world’s biggest cities and about half of the global population live within 100 kilometers (60 miles) from the ocean. That’s pretty important, especially given the huge amount of land that isn’t near a coastline. We’ve talked about riverine flooding caused by intense precipitation in a previous video. But, there’s another type of flooding that has almost nothing to do with rain and almost everything to do with air.