Sullivan’s Island Beach Flooded by Sudden Wave Surge: Was it a Ship’s Wake?

Sudden Flood-wave Stuns Visitors at Sullivan’s Island Beach

SULLIVAN’S ISLAND, SC — August 3, 2025
At approximately midday, beachgoers on Sullivan’s Island were surprised when a powerful wave surged nearly 100 feet inland, drenching towels, lawn chairs, and belongings with ocean water. The flooding wave lasted about 30 seconds. It arrived without warning—on an otherwise calm and sunny day.

Witnesses reported a large ocean liner entering the channel just offshore moments before the surge hit. This sparked speculation that the ship’s wake might have caused the abrupt flooding.

“It wasn’t a retreat—it was a full-on wave. It didn’t crash violently, but it just kept coming fast,” said one local. “We saw people scrambling to pull their beach gear back before it got washed away.”

Could a Ship Wake Cause This Type of Event?

Displacement and the Bernoulli Effect

Experts suggest that large vessels can indeed cause shoreline flooding under certain conditions, especially in narrow or shallow waterways. The approach to Charleston Harbor passes directly alongside Sullivan’s Island.

As ships displace massive volumes of water while moving, they create a depression or drawdown around the hull. This is related to the Bernoulli Effect, where water accelerates around the moving vessel, lowering local pressure and water level. When this displaced water rebounds again, it can result in a secondary surge. Upon reaching the shoreline, it becomes a localized wave event.

“This displacement draws water away, creating a temporary void that then rushes back in,” explained a coastal marine engineer. “In certain conditions, that rebound can appear as a quick, strong wave—almost like a localized mini-tsunami.”

“Mini-Tsunami” Phenomenon

This type of event is often referred to as a “mini-tsunami,” a colloquial term used to describe temporary flooding caused by man-made or localized natural wave events. It is not related to tectonic activity.

Several conditions can amplify this effect:

• Confined waterways: In places like Sullivan’s Island Channel, where depth is limited and space is narrow, wake energy doesn’t dissipate easily.
• Shallow shorelines: As the wave approaches land, the shallow gradient allows energy to concentrate, lifting the wave higher. This pushes it inland.
• Large vessel movement: The more water displaced, the greater the potential for a pronounced rebound effect on nearby shores.

Similar Incidents Are Not Unheard Of

The U.S. Army Corps of Engineers has previously studied the impact of large commercial vessels passing close to recreational beaches. This is an observation particularly along the Georgia and South Carolina coasts. In Tybee Island, multiple reports of ship-generated surges prompted scientific investigation in recent years (wjcl.com).

According to local floodplain data, Sullivan’s Island is a Special Flood Hazard Area. Events like this could increase in frequency with rising sea levels, reduced beach width, and more frequent marine traffic (sullivansisland.sc.gov).

Eyewitness Reports and Public Reaction

The wave caught dozens of people off guard.

“It just came up the beach so fast. We didn’t know if it was a tide thing, or a freak wave, or something worse,” said a family visiting from Charleston.

Others nearby pointed toward the channel.

“We saw the liner going in—it was huge—and about two minutes later the beach started to flood. I wouldn’t say it was dangerous, but it was enough to make you run and grab your stuff.”

Was This Dangerous?

Experts say that while this event was not life-threatening, it does underscore the need for awareness around vessel-induced surges. This is particularly important in areas where commercial and recreational traffic share close quarters.

“If children had been playing right at the shoreline, or if someone was sunbathing closer to the water, this could’ve knocked them over,” one safety expert said.

Next Steps

No injuries were reported. Town officials have not issued an official statement as of publication time, but residents are encouraged to:

• Stay alert to large vessels passing near shorelines.
• Avoid placing belongings too close to the water, even during calm weather.
• Share any photos or video with local officials or news outlets for investigation.

Final Thoughts

While dramatic, the sudden wave at Sullivan’s Island is likely a case of a large ship entering a confined channel. This triggered Bernoulli drawdown and wave rebound that surged inland unexpectedly. Combined with coastal conditions and shallow bathymetry, the result was a rare, fascinating, and startling mini-flooding event.

If you were on the beach during the wave and have video or images to share, please contact Presence News. We’ll update this article as more information becomes available.