As relative sea level increases, it no longer takes a strong storm or a hurricane to cause coastal flooding. Flooding now occurs with high tides in many locations due to climate-related sea level rise, land subsidence, and the loss of natural barriers.
Nuisance flooding—which causes such public inconveniences as frequent road closures, overwhelmed storm drains and compromised infrastructure—has increased on all three U.S. coasts, between 300 and 925 percent since the 1960s. In a 2014 NOAA technical study, eight of the top 10 U.S. cities that have seen an increase in nuisance flooding are on the East Coast.
The effects of rising sea levels along most of the continental U.S. coastline are expected to become more noticeable and much more severe in the coming decades, likely more so than any other climate-change related factor. Any acceleration in sea level rise that is predicted to occur this century will further intensify nuisance flooding impacts over time, and will further reduce the time between flood events.