North Atlantic Tropical Cyclones and U.S. Flooding

Riverine flooding associated with North Atlantic tropical cyclones (TCs) is responsible for large societal and economic impacts. The effects of TC flooding are not limited to the coastal regions, but affect large areas away from the coast, and often away from the center of the storm. Despite these important repercussions, inland TC flooding has received relatively little attention in the scientific literature, although there has been growing media attention following Hurricanes Irene (2011) and Sandy (2012). Based on discharge data from 1981 to 2011, we provide a climatological view of inland flooding associated with TCs, leveraging on the wealth of discharge measurements collected, archived, and disseminated by the U.S. Geological Survey (USGS). Florida and the eastern seaboard of the United States (from South Carolina to Maine and Vermont) are the areas that are the most susceptible to TC flooding, with typical TC flood events that are two to six times larger than the local 10-year flood peak, causing major flooding. We also identify a secondary swath of extensive TC-induced flooding in the central United States. These results indicate that flooding from TCs is not solely a coastal phenomenon, but affects much larger areas of the United States, as far inland as Illinois, Wisconsin and Michigan. Moreover, we highlight the dependence of the frequency and magnitude of TC flood events on large scale climate indices, and highlight the role played by the North Atlantic Oscillation and the El Niño-Southern Oscillation phenomenon (ENSO), suggesting potential sources of extended-range predictability.