If you’re out and about around Folly and the water along our coastline seems extremely high, it could be when king tides are in town. A natural phenomenon that occurs a few times a year, these tides can reach 7 ft. or higher — bringing with them the distinct possibility of coastal flooding.
Interestingly enough, although certainly now adopted as a colloquialism, the term “king tides” isn’t a scientific one. “The ‘king tide’ is an informal term given to high tides anywhere,” Brian McNold of the University of Miami’s Rosenstiel School of Marine and Atmospheric Science told Accuweather. “It’s just an alignment of the moon and sun that tugs our ocean farther away [or] toward the surface than normal.”
Think of it this way, puts National Geographic: all tides happen due to the gravitational pull of the moon and to a lesser extent the sun, right?
Since gravity is at its strongest at short distances, the moon exerts greater gravitational pull on the side of the Earth closest to it — the oceans on that side then are pulled more strongly toward the moon than the oceans on the other side. This is the gist of high and low tides, with the high tides being on the side affected more by the gravitational pull of the moon.
How do we get king tides?
In order for king tides to occur, a few specific things have to happen. First, when the moon, Earth, and sun align, the sun’s gravitational pull causes tides to be a bit higher. When this happens, it is called a spring tide. Additionally, a perigean tide occurs when the moon is at its closest approach to Earth on its elliptical orbit.
King tides are essentially the result of these two astronomical events syncing up, resulting in Earth, sun, and moon being as close as possible to each other in their relative orbits.
How often do king tides occur?
Because king tides occur naturally and regularly, they are fairly easy to predict. King tides occur once or twice every year
in coastal areas, like Charelston. In the United States, they are predicted by the National Oceanic and Atmospheric Administration (NOAA). Over time, the frequency and effect of King Tide events may increase due to gradual mean sea level rise.
Is there any correlation between king tides and global warming?
Scientists underscore that king tides are a natural and cyclical phenomenon. However, you can look at them as somewhat of a preview of things to come. “We expect that it’s roughly equivalent to what a normal tide would look like under sea level rise in 50 years,” says Sara Aminzadeh, executive director of the California Coastkeeper Alliance.
Is there anything I should do during a king tide?
Take pictures! The South Carolina Department of Health and Environmental Control (DHEC) needs your help documenting the effect that extreme tidal events have on our Lowcountry beaches. The organization asks that you take photographs of king tide events and send them in.
They will then analyze these photos and include them in the long-term analysis of coastal vulnerability and plans address it.