Urban development and climate change to trigger severe urban floods Urban floods are about to become that much worse. The residents of northern Georgia, US, aren’t very used to flooding. So when severe rain started falling in September 2009, most people didn’t pay much attention. But the rain kept falling and falling, submerging entire neighborhoods, roads, and bridges. The Georgia flood seemingly came out of nowhere, but results from a new study suggests it may have not been all that much of a freak occurrence. Instead, it may be the result of the combined effect of urban development and greenhouse gases.