South Carolina and much of the Southeast coastline are bracing for some of the highest water levels of the year as October’s King Tide event combines with persistent onshore winds, elevating the risk of flooding.
According to the National Weather Service in Charleston, astronomical tides will be elevated through the workweek due to the full moon in combination with other factors.
“Persistent favorable winds have the potential to produce up to major coastal flooding by the latter part of next week,” the National Weather Service office in Charleston said in a recent forecast discussion.
Forecasts show water levels reaching minor to moderate flood stage from the Savannah River to the Charleston Harbor and around Myrtle Beach.
The Harvest Full Moon will officially peak on Monday; however, perigee, when the moon makes its closest approach to Earth, won’t occur until Wednesday morning, which could help to prolong the flooding event.
Charleston-area impacts
The NWS cautions that saltwater inundation is likely across many downtown Charleston roadways and expecting water levels to peak on Tuesday at around 7.8 feet.
Roads that could be impacted include Market Street, East Bay, and Rutledge, as well as areas around the campus of the Medical University of South Carolina.
In nearby Beaufort County, flooding will likely impact Hunting Island and the Sea Island Parkway near the Chowan Creek Bridge.
At 8 feet, a major flood event is considered to be underway with numerous flooded roadways and water intrusion into structures.
Water levels last approached 8 feet during a significant coastal storm that impacted the Carolinas in Nov. 2024.
During the event, dozens of roadways were closed and transportation crews deployed barricades to prevent drivers from venturing through floodwaters.
Tides are expected to remain below levels reached during Tropical Storm Idalia in 2023 and Hurricane Matthew in 2016, when the water gauge at the harbor reached between 9–10 feet.
The City of Charleston has made it easy for residents and visitors to monitor tide levels and see the latest road closures: Click here.
Impacts beyond Charleston
Other coastal communities, including Myrtle Beach, Beaufort, Hilton Head and the barrier islands around Savannah, all could see flooding during periods of high tide throughout the week.
High tides in the southern part of the state will generally fall between 8 a.m. to 11 a.m. and again from 8 p.m. to 11 p.m.
Further north around Myrtle Beach, the higher tides will generally occur between 9 a.m. and noon and from 9 p.m. to around midnight.
The NWS advises boaters to be cautious around bridges, where clearances will be reduced, and to avoid docking around flood zones.
Despite the moon’s waning influence by the end of the week, a backdoor cold front could help to kick up gusty winds, leading to additional flooding concerns.