Ever Seen A Beach Disappear? Experts Explain Sea Isle Phenomenon

SEA ISLE CITY, NJ — Ever seen a beach disappear? It briefly looked that way Thursday in Sea Isle City, when a Townsends Inlet Beach rapidly eroded.

The viral video generated more than 3 million views across social media platforms. The video shows large chunks of sand breaking into the water like a crumbling cliff.

Such an event is rarer than finding an oyster's pearl. Dr. Stewart Farrell, director of Stockton University's Coastal Research Center, only knew of two such occurrences in New Jersey before he saw the Sea Isle video.

The phenomenon occurred on a beach south of 94th Street, where several factors likely contributed to the rapid erosion, Farrell said.

Water flows at 3-4 feet per second in the channel between Sea Isle and Avalon — the area under the Townsends Inlet Bridge. The speed is "second to none" among New Jersey waters, according to Farrell.

"The channel is right there," he said. "So if you step off the sand into the water and you’re not fully cognizant of what’s going on, you’re on your way either into the salt marshes or out to Portugal really fast."

The Townsends Inlet channel reaches depths of up to 65 feet. Nothing holds the sand together besides gravity, Farrell says. So if a slope gets steep enough, it essentially creates a "marine landslide," he said.

That beach has always been an erosion hotspot because of its channel location, according to Dr. Thomas O. Herrington, associate director of Monmouth University's Urban Coast Institute.

The New Jersey Department of Environmental Protection constructed a jetty to the east to help slow erosion, Herrington says. The plan has worked well, allowing sand to build up along the inlet beach until the beach gets so large it encroaches on the inlet channel, he said.

"When that happens, the inlet currents eat away at the sand, causing the cliff like erosion you see in the video," Herrington said. "It is all designed to happen that way and should not be considered out of the ordinary."

In fact, the groin was designed to help sand to move over into the inlet, so it didn't disturb a nesting area for piping plovers, said Dr. J. Richard Weggel of Drexel University's Department of Civil Architecture & Environmental Engineering.

Farrell only knows of two other similar instances since he started working in New Jersey in 1971: 2012 in Holgate on Little Egg Inlet and 2016 along Hereford Inlet in North Wildwood.

The Holgate episode included instantaneous slope failure, where sand slid into the channel. The ground shook underneath two people fishing, and 300 feet of beach eroded. The North Wildwood occurrence featured a slump similar to the Sea Isle City one.

Certain tidal conditions also contribute an event like Sea Isle's. All this took place right before a full moon, said Mayor Leonard C. Desiderio. Sea Isle's Department of Public Works helped remedy the issue by using heavy equipment to move around sand and flatten the beach.

"I hope that the video will serve as a reminder of the power of the ocean and why people should only swim on designated bathing beaches while lifeguards are on duty," Desiderio said.

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