Last updated July 11, 2019

Increasing risk of compound flooding from storm surge and rainfall for major US cities

  • States that when storm surge and heavy precipitation co-occur, the potential for flooding in low-lying coastal areas is often much greater than from either in isolation
  • Determines the likelihood of joint occurrence of these two phenomena for the contiguous United States (US) and show that the risk of compound flooding is higher for the Atlantic/Gulf coast relative to the Pacific coast
  • Provides evidence that the number of compound events has increased significantly over the past century at many of the major coastal cities
  • Finds that long-term sea-level rise is the main driver for accelerated flooding along the US coastline; however, under otherwise stationary conditions (no trends in individual records), changes in the joint distributions of storm surge and precipitation associated with climate variability and change also augment flood potential
  • Looks at New York City (NYC)—as an example—and finds the observed increase in compound events is attributed to a shift towards storm surge weather patterns that also favor high precipitation