According to a recent article by Seth Borenstein of Associated Press, a recent study of hurricane frequency by Princeton scientists shows that the chances of two hurricanes hitting a single location in a short period of time has increased from once every few decades to once every two or three years. This would have big implications for coastal communities who might be reeling after a single hit and would be unprepared for a second storm to hit so soon after the first one. But this has occurred in both Louisiana and Florida in recent years, so it does appear to be happening more often now than in the past. You can read more about it at AP.