Carolina’s king tides explained
King tides are a part of life on the oceanfront, bringing higher than average high tides ashore. This can mean some low-lying areas of the Grand Strand flood multiple times a year, often a headache for residents and visitors alike.
The scientific name for a king tide is a perigean spring tide, which means that the earth, moon and sun are aligned during a new or full moon while the moon is as close as it gets to the Earth during its orbit.
The impacts of a king tide can range from local nuisance flooding to more obstructive, damaging floods, according to National Weather Service warning coordination meteorologist Steve Pfaff. How bad it gets often depends on other factors, Pfaff said, especially wind direction and any storms in the area. Onshore winds and heavy rains can lead to high tides that peak above 8 feet compared to more typical high tides that peak around 5 feet. Better weather can mean lower king tides.
Those factors help determine whether or not the weather service issues a coastal flood advisory or warning during a king tide, according to Pfaff. He added that in his 20 years with the weather service in Wilmington, North Carolina, he has seen an increase in the number of advisories and warnings because of king tides.
The tides can have a lasting impact on beaches. On the Outer Banks of North Carolina, king tides were blamed for creating a 10-foot cliff on the beach in Nags Head.
Some Grand Strand residents, like Ed Black of Garden City, say that they consistently see flooding during king tides. Black said he regularly sees water on his street during higher than normal tides. Areas of Pawleys Island have little to no beach left during king tides.
The number of king tides that happen in a year can vary, and they happen during every season. Sometimes more than one will occur within a single month. Other times, months will pass between them. It all depends on the orbits of the earth, moon and sun.
King tides usually last 3-5 days.
Sea level rise may increase the frequency and impact of king tides, according to DHEC’s website. DHEC asks that people send in photos of king tide flooding through a mobile app to help the agency learn more about how they affect South Carolina. That research is part of a national project, the King Tides Initiative.
Coastal residents and visitors can track king tides and see how high the tide will be and when it will peak using a tide chart.