Federal forecasters say U.S. coastlines could see an increase in high-tide flooding over the next year thanks to climate change and a stronger El Niño. That includes many parts of the Carolinas' coast and Pamlico Sound.
The annual high-tide flooding outlook from the National Oceanic and Atmospheric Administration, or NOAA, predicts that the Carolinas could see an average of four to eight days over the next year when high tides are 1 to 2 feet higher than normal. The average was six days from May 2022 to April 2023.
Sea level rise and sinking land are key factors, NOAA oceanographer William Sweet said.
"In the Pamlico Sound, areas (that) are very flat, very low-lying along Highway 12 on the Outer Banks. You name it. There's a lot of land subsidence going on in the upper parts of North Carolina," Sweet said.
"This area is exposed to tropical storms, it's exposed to extra-tropical storms or Nor'easters and high rates of sea level rise. Areas like Beaufort and Wilmington, North Carolina, Manteo, water is creeping up in the stormwater drains and back flowing into the streets," he said.
Duck, at North Carolina's Outer Banks, had 13 high-tide flood days in the past year, the most in the Carolinas. It could see a similar number in the coming year.
But the biggest increases could come in Wilmington, where four to eight days are predicted compared to two days last year, and in Charleston, which could see six to 10 days of high-tide floods this year, up from just three last year.
The seasonal weather pattern known as El Niño, which is making air and water temperatures hotter, will also fuel the increase. NOAA said El Niño is expected to increase the frequency of high-tide flooding on both East and West coasts.
Meanwhile, NOAA also introduced a new month-by-month outlook that predicts where and when high-tide flooding might occur over the coming year in locations where the agency has high-tide gauges.
Nicole LeBoeuf, director of NOAA's National Ocean Service, said the tool can help communities and emergency planning officials better prepare.
"Coastal communities can use this authoritative information to make informed decisions about flooding risks, like whether to close roads, perform maintenance on storm drainage systems, or prepare for emergency protections for other vulnerable infrastructure," LeBoeuf said.
