Coastal flooding increasing by ‘leaps and bounds’ in South Carolina, Georgia

The rate of the rising sea is a major issue of debate for many coastal communities. But no matter how fast or slow the sea is rising, coastal flooding is increasing by “leaps and bounds,” according to a recently released report.

Charleston and Savannah both broke records for the number of flooded days during the 2016 meteorological year, according to an National Oceanic and Atmospheric Administration report released Wednesday.

The Beaufort County area was not specifically mentioned in the report, because the county’s closest tide gauge is Savannah’s at Fort Pulaski, Ga.

But located in middle of the two cities, the county faces similar flooding concerns.

NOAA oceanographers reported that tidal flooding struck Charleston 50 days and struck Savannah 38 days from May 2016 through April 2017.

Those numbers were up from 38 days of flooding in Charleston in 2015, which was a previous record, and 34 days of flooding in Savannah in 2015.

Flood frequencies have increased nearly 50 percent in Savannah from 2013 to 2016, according to the report.

“There’s a higher than expected trend occurring over the Southeast Atlantic, where sea levels have inched up more and more over the last couple years, and seasonally high tides are exceeding threshold for minor impacts,” Sweet said.

The number of flooded days accounts for days that exceeded the local threshold for minor flooding, as defined local emergency managers and Weather Forecast Offices of NOAA's National Weather Service, according to Sweet. The thresholds are similar in Charleston and Savannah, 0.38 and 0.46 meters above average highest tide, respectively.

Tide gauges, including those in Charleston and Fort Pulaski, Ga., have observed a rapid acceleration in annual high tide flood frequencies along the coastline over the last several decades due to rising sea level, the report said.

“It’s important to note that the trends that indicate sea level increases from year to year aren’t linear — they’re accelerating,” Sweet said. “It’s not increasing gradually, and that’s the unfortunate news.”

While other coastal counties in South Carolina have received preliminary flood maps in recent months, Beaufort County property owners are still awaiting their maps — to replace the oldest ones in the state.

The S.C. Department of Natural Resources, which said in December to expect Beaufort County’s flood maps sometime in the spring, now says it will have the maps in early summer.

This story was originally published June 8, 2017 at 6:38 PM with the headline "Coastal flooding increasing by ‘leaps and bounds’ in South Carolina, Georgia."