A photo of the breach area in Fire Island taken on...

A photo of the breach area in Fire Island taken on April 21, 2018. Credit: School of Marine and Atmospheric Sciences, Stony Brook U./Charles Flagg

The breach that opened west of Smith Point during Superstorm Sandy has narrowed dramatically over the past several years, recent aerial photos and data show. But when or if it will close completely remains unknown, experts said.

In an interview last week, Stony Brook University research professor Charles Flagg of the School of Marine and Atmospheric Sciences said the influx of sand into and around the breach has sharply reduced the depth of the major channel through the waterway. At its deepest during the past decade, it had been 15 to 20 feet. Now, he said, the water channel is just over 6 feet.

"It was hard for us to even get there," he said of his last visit. "We were stumbling over shoals."

In a report a year ago, Flagg wrote channel depths and cross-sectional area of the breach "have been reduced to maybe less than half what they were" in the early days of its formation. The trend continued during 2021.

In addition, the reduced inflow of saltier ocean water is beginning to show in bay salinity levels, Flagg said. Data from Bellport Bay shows salt content gradually decreasing, from levels as high as 33 parts per thousand in 2013 and 2015 to about 27 parts per thousand now.

The lower exchange of ocean water could affect water quality.

"The main impact of the breach was to clean the water in Bellport Bay and to some extent Patchogue Bay," Flagg said. "There’s fishing in Bellport Bay that hasn’t been seen in decades. Sea grass is beginning to respond. And for a while we held the brown tides at bay — all because the exchange reduced the pollution levels in the bay … Water was so clear you could see to the bottom at times."

John Tanacredi, a professor of earth and environmental studies and director of the Center for Environmental Research and Coast Oceans Monitoring at Molloy College, also has observed the breach's "influence on the water quality of the Great South Bay," including increases in salinity. He noted dissolved oxygen levels and overall water quality have been "outstanding," in past years and said it’s "reflected in the diversity of organisms" in the bay.

While noting the breach has been "slowly closing on its own," Tanacredi said it’s anyone’s guess how long full closure may take. "It could be another decade," he said.

A visit by Newsday in December at low tide showed a massive field of sand that had formed on the eastern side of the inlet — perhaps 100 yards square. Flagg said westward buildup is not uncommon on the ever-changing Fire Island shore. He noted the Fire Island Light House once stood at the edge of the Fire Island inlet, which over the years has built up five miles of sand to the west.

"It’s all new territory," including Robert Moses State Park, he noted.

Flagg's prognosis for the new breach excludes a timeline.

"Clearly it’s heading toward closure," he said. "No natural breach ever lasts very long. Eventually it will pinch off."

He noted prior estimates had projected a closure anywhere from 60 days to six months to six years — all wrong. For that reason, Flagg said, "I’m not going to venture a timeline as to when it will fully close. I have no idea."

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