As the planet gets hotter, sea levels will rise and coastal waters will warm, bringing more damaging rainstorms. Scientific modeling of these changes predicts a sea level rise of 1 inch per year, causing coastal waters to reach farther inland and exposing more homes to flooding. Groundwater levels will rise and stormwater drainage systems will be overwhelmed by repeated flooding. Explore the impacts below, watch nextLI's documentary on this threat and share your flooding experiences.

Long Island

What does this mean for Long Island?

This map combines New York State Energy Research and Development Authority 100-year floodplain data with the National Oceanic and Atmospheric Administration's predictions for the Northeast USA. The map shows which areas of Nassau and Suffolk counties are likely to experience severe flooding by 2050.

Mastic Beach

A home purchased in the shaded areas in 2020 could have as much as a 26% chance of experiencing at least one severe flood during the life of a 30-year mortgage.

By 2100, that risk could rise to 45% and include hundreds more homes and structures.

In the last decade, the Town of Brookhaven bought out around 300 parcels of land to restore the surrounding salt marsh and has abandoned local roads that are at sea level.

Long Beach

To estimate the probability of flooding in the future, scientists look to the past. The frequency of historic flooding events alongside future climate change predictions helps us understand how susceptible a neighborhood is to flooding.

As a half-mile-wide barrier island, the entire City of Long Beach is already severely susceptible. Long Beach has undergone a $230 million shoreline storm protection project since Superstorm Sandy in 2012 that included creating 16-foot-tall dunes, adding 1.2 million tons of sand and building 15 jetties. These measures are largely temporary.


Over the next several decades, about $1.5 billion of federal funding will be spent on replenishing and fortifying Long Island's shores through the 'Fire-Island Inlet to Montauk Point Project.'

The U.S. Army Corps of Engineers has already placed about 475,000 cubic yards of dredged offshore sand on the beach stretch from Kirk Park Beach to South Edison Beach. This narrow floodplain area is highly susceptible at Napeague Bay where coastal and tidal waters could spill over Route 27, the only access road, cutting Montauk off from the rest of the South Fork.

North Shore

Long Island's northern coastline sits at a higher elevation than the South Shore, but is still vulnerable to storm surge-induced flooding and bluff erosion, which threatens to collapse buildings and homes.

In Port Jefferson, an ongoing $10 million effort to stem erosion includes plans to construct a wall on top of the bluff that would divert stormwater away from the cliff.


Away from the coast, mid-Island experiences its share of flooding due to more intense and frequent storms. With less open space to absorb the increased amount of water, old drainage systems with small pipes are being overwhelmed in Nassau and Suffolk.

This analysis uses a high sea level rise scenario as estimated by NOAA. It hypothesizes the worst-case scenario as of 2009, when the Federal Emergency Management Agency last compiled the data upon which the projections are based. The expanse of land at risk on Long Island is expected to be larger when the flood maps are updated. The analysis is an estimate of the likelihood of flooding based on mathematical probabilities; actual flood occurrences can vary.

Take a look at the map below to discover whether your neighborhood is potentially vulnerable.

Floodplain projections

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Data analysis by Karthika Namboothiri. Development by Mark Levitas, TC McCarthy, Christopher McLeod, Kavita Mehta. Design by Jennifer Brown, James Stewart. QA by Daryl Becker and Sumeet Kaur.


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