Coastal communities in South Carolina and around the Southeast face another round of flooding this week as the month’s full moon leads to higher water levels known as king tides.
The higher tides are the result of the full moon’s gravitational pull and its closest approach to Earth, known as its perigee.
Even though the lunar impact will be the strongest of the year, causing water levels to rise between 1 and 3 feet, forecasters expect tides in most communities to remain below the levels reached in October.
October’s high tides coincided with an unusually strong onshore flow and tropical cyclones spinning in the western Atlantic, which helped elevate water levels and cause substantial coastal flooding.
Still, this week’s event could be significant enough to trigger Coastal Flood Advisories for counties such as Jasper, Beaufort, Colleton, Charleston, Georgetown and Horry.
National Weather Service meteorologists expect water levels to reach moderate flood stage around Charleston Harbor and minor flood stage near the entrance to the Savannah River during the middle of the week before tapering off closer to the weekend.
Residents in low-lying areas, especially those near tidal basins, could notice water overtake docks and boat ramps, particularly during morning high tide cycles.
At high tide, some roadways and walkways also typically close when water levels reach their peak.
Fortunately, no additional rainfall is expected this week, which would otherwise worsen flooding and create travel problems.
Saltwater can be damaging to vehicles, which is why local authorities often advise residents to seek alternate routes. If driving through water is unavoidable, motorists are urged to wash their vehicles afterward to minimize potential corrosion.
After this week’s king tide event, only one more supermoon remains this year - the Cold Moon on Dec. 4. While this event is also expected to produce higher tides, forecasters do not anticipate the same level of coastal impacts seen during either October or November.
Looking ahead, three supermoons are expected to light up the night sky in 2026 - the Wolf Moon on Jan. 4, the Beaver Moon on Nov. 24 and the Cold Moon on Dec. 23.
The lunar cycle means the increased tidal levels will largely avoid overlapping with the 2026 Atlantic hurricane season, which typically peaks during the late summer and fall.
When supermoons and tropical systems align, the resulting storm surge and astronomical tides can lead to severe coastal flooding, which is not only damaging but deadly.
According to NOAA, roughly 90% of direct deaths attributed to tropical cyclones result from flooding, rip currents and other water-related impacts.