Home

Climate Change Indicators

Climate Change Indicators: Coastal Flooding

This indicator shows how the frequency of coastal flooding has changed over time. 

  • Map with bar graphs showing changes in the frequency of flooding along the U.S. coastline between the 1950s and 2010s.
    Download Data  Download Image  KMZ Icon
     
     

    This map shows the average number of days per year in which coastal waters rose above the local threshold for minor flooding at 27 sites along U.S. coasts. Each small bar graph compares the first decade of widespread measurements (the 1950s in orange) with the most recent decade (the 2010s in purple).

    Data source: NOAA, 20163
    Web update: August 2016

Key Points

  • Flooding is becoming more frequent along the U.S. coastline. Nearly every site measured has experienced an increase in coastal flooding since the 1950s (see Figure 1). The rate is accelerating in many locations along the East and Gulf Coasts (see Figure 2).
  • The Mid-Atlantic region suffers the highest number of coastal flood days and has also experienced the largest increases in flooding. Since 2010, Wilmington, North Carolina, has flooded most often—49 days per year—followed by Annapolis, Maryland, at 46 days per year. Annapolis, Wilmington, and two locations in New Jersey (Sandy Hook and Atlantic City) have also seen some of the most dramatic overall increases in frequency: floods are now at least 10 times more common there than they were in the 1950s. The Mid-Atlantic’s subsiding land and higher-than-average relative sea level rise both contribute to this increase in flooding (see the Sea Level indicator).
  • Flooding has increased less dramatically in places where the local flood threshold is higher (for example, the Northeast and locations on the Gulf of Mexico) or where relative sea level has not risen as quickly as it has elsewhere in the United States (for example, Hawaii and the West Coast, as shown by the Sea Level indicator).

References

1. Melillo, J.M., T.C. Richmond, and G.W. Yohe (eds.). 2014. Climate change impacts in the United States: The third National Climate Assessment. U.S. Global Change Research Program. http://nca2014.globalchange.gov.

2. Trtanj, J., L. Jantarasami, J. Brunkard, T. Collier, J. Jacobs, E. Lipp, S. McLellan, S. Moore, H. Paerl, J. Ravenscroft, M. Sengco, and J. Thurston. 2016. Chapter 6: Climate impacts on water-related illness. The impacts of climate change on human health in the United States: A scientific assessment. U.S. Global Change Research Program. https://health2016.globalchange.gov.

3. NOAA (National Oceanic and Atmospheric Administration). 2016 update to data originally published in: NOAA. 2014. Sea level rise and nuisance flood frequency changes around the United States. NOAA Technical Report NOS CO-OPS 073. https://tidesandcurrents.noaa.gov/publications/NOAA_Technical_Report_NOS_COOPS_073.pdf.

4. NOAA (National Oceanic and Atmospheric Administration). 2016 update to data originally published in: NOAA. 2014. Sea level rise and nuisance flood frequency changes around the United States. NOAA Technical Report NOS CO-OPS 073. https://tidesandcurrents.noaa.gov/publications/NOAA_Technical_Report_NOS_COOPS_073.pdf.


Printer-friendly PDF of all text and figures

Learn about other indicators in this section

Ocean Heat Sea Surface Temperature Sea Level Land Loss Along the Atlantic Coast Coastal Flooding Ocean Acidity