State environmental officials are asking for help in documenting unusually high tides Sunday in Beaufort County and up the state's coast.
The expected higher seas are the result of a phenomenon known as "king tides," which can be can be as much as 1 to 2 feet higher than the normal tide range, according to the S.C. Department of Health and Environmental Control.
King tides occur when the moon is at its closest to Earth, and when both Earth and moon align with the sun during a new or full moon, according to DHEC.
That's expected to happen Sunday night when the moon will become full within the same hour its orbit reaches its closest point to Earth, according to NASA Science. The "supermoon" will appear 14 percent bigger and 30 percent brighter than typical full moons.
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With the full moon approaching, the king tides began Friday and are expected to last through Tuesday night, with the high-tide peak during the supermoon Sunday night.
To study how the higher tides might affect low-lying coastal communities, DHEC is recruiting residents along the state's coast to photograph what happens in their areas and submit them to mycoast.org. DHEC will map where each photo was taken to document the effects and better predict the high tides, according to the website.
Where typical high tides in Beaufort County might range 6 to 7 feet, the National Oceanic and Atmospheric Administration predicts tides 9 feet or more at their peak Sunday evening.
Historic Beaufort Foundation director Maxine Lutz and photographer Paul Keyserling will document the effects Sunday night in downtown Beaufort near King and East streets, Lutz said. That area has flooded several times during heavy rains this summer and may be the most likely place to see any flooding from the extreme tides, Lutz said.
The king tides also could offer a glimpse into how rising sea levels might eventually affect coastal communities, according to Frank Knapp, president and CEO of the S.C. Small Business Chamber of Commerce. A recent analysis by nonprofit climate-research group Climate Central predicted extreme flooding in the next 20 to 40 years from rising sea levels and storm surges.
Knapp, who recruited Lutz to aid DHEC's effort, is helping organize residents in Charleston and North Myrtle Beach to document the tides.
Rain would exacerbate the higher tides and could lead to some flooding. The National Weather Service predicts a 50 percent chance of precipitation Sunday night.
Follow reporter Zach Murdock at twitter.com/IPBG_Zach.