Sea level rise is increasing the number of nuisance flooding events on all three U.S. coasts, and the largest increase in these events is happening right here in the Mid-Atlantic, according to a report released by the National Oceanic and Atmospheric Administration.
Annapolis, Md. and Baltimore, Md. have by far seen the highest percent increase in nuisance flooding events since the 1960s. The study, which analyzed data from 45 water level gauges around the country, found that the number of these events in Annapolis has increased 925%. Baltimore has seen an increase of 922%. The third-ranking city on the list is Atlantic City, N.J., with a 682% increase.
Washington D.C. (8th, 373%) and Norfolk, Va. (10th, 325%) were in the top ten, as well. In fact, eight of the top ten cities that have seen an increase in nuisance flooding are on the East Coast.
In Annapolis, the average number of nuisance flood days from 1957 to 1963 was 3.8. From 2007 to 2013, that number had increased to 39.3. In D.C., the number increased from 6.3 days to 29.7.
Nuisance flooding is exactly what it sounds like — a nuisance. It clogs storm drains, closes roads, and makes your day a little bit more difficult. It’s the kind of event where the water level seeps onto higher ground, but causes no major property damage. It is technically covered by the National Weather Service as “minor flooding.”
Worldwide, sea level has risen about eight inches since the late 1800s, the result of warming ocean water, melting glaciers and ice caps, and the ever-decreasing Greenland and West Antarctic ice sheets. However, sea level hasn’t risen the same amount in every location. Some locations are less lucky than others, including the eastern and Gulf coasts of the United States (where sinking land exacerbates sea level rise), and earlier this year the National Climate Assessment projected that sea level will continue to increase one to four feet by 2100.
According to NOAA oceanographer William Sweet, lead author on the report, the uptick in minor flooding gives us a glimpse into the future of more serious events. “The effects of rising sea levels along most of the continental U.S. coastline are only going to become more noticeable and much more severe in the coming decades,” says Sweet. “Probably more so than any other climate-change related factor.”
— Kori Anderson (@koranders) May 16, 2014
The full list of cities and percent increases from the report:
Annapolis, Md.: 925%
Baltimore, Md.: 922%
Atlantic City, N.J.: 682%
Philadelphia, Pa.: 650%
Sandy Hook, N.J.: 626%
Port Isabel, Texas: 547%
Charleston, S.C.: 409%
Washington, D.C.: 373%
San Francisco, Calif.: 364%
Norfolk, Va.: 325%