On a cloudless morning two years ago, shortly after Danielle Smith moved into a new apartment in Far Rockaway, Queens, she looked out of her window and saw a swan gliding by.
Overnight, the street in front of her home had become a creek.
That morning, Ms. Smith, a 36-year-old mother of five, learned that she was living in one of the most vulnerable areas in the city to high-tide flooding.
A hundred thousand New Yorkers currently live in low-lying coastal neighborhoods affected by chronic flooding. About half of them, like Ms. Smith briefly, reside in the working- and middle-class enclaves surrounding Jamaica Bay.
In the Rockaways, a low-lying peninsula in Queens that separates the Atlantic Ocean from Jamaica Bay, life has long been shaped by the tides. High-tide floods are not caused by the weather but by the twice monthly alignment of the Earth, sun and moon. When there is a full or a new moon, the sun and moon exert a gravitational pull that causes tides to swell.
But as climate change causes sea levels to rise, high tide floods — sometimes called nuisance floods or sunny-day floods because they can happen on clear days — are likely to inundate more coastal neighborhoods across the five boroughs.
By 2050, Lower Manhattan could see 85 days of high-tide flooding annually, a fivefold increase. By the end of this century, 600,000 city residents could be affected by regular tidal flooding, according to the New York City Comptroller’s office.
“Tidal flooding is a pretty significant existential climate threat,” said Louise Yeung, the chief climate officer for the comptroller’s office. “So how do we, as a city, grapple with these kinds of threats where some neighborhoods will be permanently or semi-regularly flooded?” she added.
The impact of tidal flooding was clear during September’s heavy rainstorm that swamped much of the city and brought the transit system to a near standstill. During the peak of morning commute, a heavy rainstorm stalled over New York at the same time as the high tide.
As rain poured down, the high tide backed up drainage pipes. Across low-lying neighborhoods, the water had nowhere to go. In the Gowanus neighborhood in Brooklyn, city sensors measured three feet of floodwater.
“Timing is everything,” said Brett Branco, executive director of the Science and Resilience Institute at Jamaica Bay, a research center based at Brooklyn College. “The chances of having those kinds of compound events, where you have sunny-day flooding coinciding with extreme rainfall events, becomes more likely with climate change, and they can amplify each other.”
Both heavy rain and tidal flooding are intensifying as the climate changes. As the atmosphere heats up, it holds more moisture and water vapor, which fuels rainstorms.
Although the tidal rhythms are shaped by the alignment of the Earth, sun and moon, sunny-day flooding is still becoming a more frequent problem because of sea level rise, which is pushing high tides even higher.
When Jamaica Bay was first developed, the land — which is filled-in marshland — was built up several inches above the water. Over time, as sea levels have risen, that protective buffer has been eroded.
“The old-timers here, myself included, can recall when the shoreline was further away than it is now,” said James Sanders Jr., a state senator, and longtime resident of the Rockaways. “We will be washed away.”
Since 2000, the east coast of the United States has experienced a 150 percent increase in annual high tide flooding days, according to the National Oceanic and Atmospheric Administration.
Sea levels are rising at nearly twice the global rate in New York City, which is sinking in part from natural, geological processes. The coastline is especially vulnerable. Centuries of development have removed vegetation, and at the same time, more housing and infrastructure have been built on low-lying land.
Tidal flooding is a more prominent concern in cities like Miami where in densely-packed areas the public is alerted in advance of tidal floods, said Nadia Seeteram, a research scientist at the Columbia Climate School who has studied the impacts of tidal flooding in Miami.
In Miami, sunny-day flooding is happening in central, high-traffic areas like downtown, among other locations. In New York, on the other hand, tidal flooding is most common in areas far from the city center, in neighborhoods around Jamaica Bay and in Staten Island.
New York is also contending with other climate extremes that cause far more visceral damage: Heat kills many more New Yorkers than flooding. Hurricanes and rainstorms cause the most monetary loss. But sea level rise, and tidal flooding, are longer-term threats.
“It’s never been the primary story in New York City, but I used to think about it on an everyday basis,” said Daniel Zarrilli, the special adviser for climate and sustainability at Columbia University who previously was the chief climate policy adviser to former Mayor Bill de Blasio. “It’s not getting the attention it deserves.”
In New York City, one of the main plans to address flooding and storm surges is to elevate: In Broad Channel, an island in Jamaica Bay, the city is raising roads, as well as requiring homeowners in many of the neighborhoods devastated by Hurricane Sandy to lift their houses.
In some new developments, city planners are starting to design areas to anticipate high-tide flooding. The shoreline park at Hunters Point South, in Queens, for example, is being renovated with native grasses and trees that absorb water. Ecologists are reinforcing areas in Jamaica Bay with berms and rebuilding “living shorelines” with native plants, which they hope will act as a buffer against high tides.
The second strategy is what’s called managed retreat, which means moving people away from the shoreline. The city has rezoned some of the highest risk neighborhoods, restricting future development there. It is also weighing the option of buying out the highest-risk homes.
“I think we’re doing the right things, but I think the challenge we face is whether we are able to do them fast enough,” said Rohit Aggarwala, the commissioner of the city’s Department of Environmental Protection. “Some of it is just how many resources can the city throw at these things in an environment of constrained budgets.”
Mr. Zarrilli said he believed that the city was pursuing the right policies but that it would have to eventually evolve. “I wonder about the sustainability of buyouts as they are currently conceived,” he said. “At some point the land is just not going to be valuable.”
For decades, longtime residents in Jamaica Bay have been adapting to life with nuisance floods. Residents in vulnerable areas know to check tide-chart apps, move their cars to higher ground and pull out their waders for a wet commute.
For many, however, tidal flooding is more than just an inconvenience. It means days off work, children missing school and skipped doctors’ appointments.
These floods can be unpredictable, depending on winds or rain. Some weeks, the high tide brings just six inches overnight, which leaves only a little puddle by morning. At other times, water can be lapping at the front door.
Ms. Smith worked as a cleaner at Barclays Center while living in Far Rockaway, but she said it was difficult to keep her job because of flooding. A few times, she had to call the police to help her take her children to school.
“It was scary,” she recalled. She said she often worried about her toddlers being caught in a flood. “The water was unpredictable.”
Shortly after she moved into the neighborhood in 2021 after living in a shelter, a social worker visited the house to assess its suitability for one of her daughters who has cerebral palsy and had been in a children’s medical facility. She was told that the flooding made it unsafe for her daughter and the medical facility’s social worker refused to discharge her to Ms. Smith.
“When we think about climate change and flooding, we think about catastrophic storms,” said Katie Graziano, a climate resilience specialist with ERG, an environmental consulting group, who has studied the impacts of tidal flooding on residents in Jamaica Bay. “But when you talk about weekly flooding, you ask, ‘When does a place start to become not livable anymore?’”
The flooding in Far Rockaway proved unlivable for Ms. Smith. Earlier this year, she moved her family to an apartment in St. Albans, Queens. Her new home was spacious and, most important to her, far inland.
“I’m just grateful we got out of that situation,” she recalled recently. “We don’t want to go through another situation like that.”
Audio produced by Jack D’Isidoro.