In cities like New York, billions of dollars in property values and government revenue are at stake, to say nothing of lives and livelihoods. The unpriced flood risks endanger the stability of the housing market, local governments, and homeowners, particularly in low-income areas. The analysis, by researchers from the Environmental Defense Fund and the nonprofit organizations Resources for the Future and the First Street Foundation, found that many overvalued properties are concentrated in coastal counties with no flood-risk disclosure laws and where there is less concern about climate change.

In a study published last month in the journal Nature Climate Change, researchers found that on federal maps, the underestimations of flood risks missed about 8 million homes and overvalued the housing market by about $200 billion. And FEMA hasn’t significantly updated many of its maps for decades. They can also create a false sense of security, by focusing on whether a property is inside or outside of a floodplain, without addressing risk to individual properties. The old floodplain maps don’t account for sea level rise, rainfall, or riverine flooding, and they can be hampered by outdated data and models. But in New York and elsewhere, the actual risks of floods and storms reach farther than most people tend to think, and farther than the prevailing federal flood maps have described. Maintained by FEMA as part of the National Flood Insurance Program, floodplain maps are meant to define mortgage risks, set insurance rates, and establish building and land-use regulations. (Click on the image to visit the interactive site.)Īnywhere along the New York waterfront ranks high for flood risk, and nearly 1.5 million New Yorkers live in the federally designated 100-year floodplain, threatened by once-in-a-hundred-year extreme storms. The Climate Mapping for Resilience and Adaptation tool combines extensive federal hazard data that can be used at national, regional, and local levels to monitor flooding conditions and explore trends. Similarly, the National Oceanic and Atmospheric Administration (NOAA) created the Digital Coast Mapper to aggregate a range of data-on coastal flooding, storm surge, and long-range inundation impacts-using a method of visualizing climate risk that was initially developed for New York in the wake of Hurricane Sandy. The White House recognized this need and created the Climate Mapping for Resilience and Adaptation tool in 2022 to surface projected exposure to climate hazards. Mapping Risks and VulnerabilityĬommunities across the US need better risk mapping. In New York City, officials are preparing a decades-in-the-making revision to federal flood maps that will, for the first time, include projections that show how climate change will impact the city’s neighborhoods. These include advances in real-time flood sensor systems, sophisticated hydrological models, and high-resolution satellite monitoring. Now, as the US federal government embarks on a historic nationwide infrastructure buildout, researchers, nonprofit organizations, and geographic information system (GIS) specialists are harnessing new technology to improve understanding of where flooding is likely and to better rank investments in resiliency. Estimates suggest that by the 2050s, sea level rise and inland floods could impact 1 of every 10 people on earth and cost cities over $1 trillion. In the US, 90 percent of natural disasters involve a flood, according to the Federal Emergency Management Agency (FEMA), making flooding the most frequent and the most expensive natural disaster in the country. These impacts underscore the growing threat climate change poses to cities like New York, especially to their most vulnerable residents.

The ferocious remnants of Hurricane Ida dropped more than three inches of rain in an hour, submerging streets and subways, and killing 11 people in flooded basement apartments. It took only 48 hours for Hurricane Sandy to overwhelm coastal neighborhoods, killing 44 people, damaging, or destroying 70,000 housing units, and leaving behind $19 billion in damages.

New Yorkers are tough, but they’re no match for an ever-weirder, ever-fiercer climate. New Yorkers have several interactive maps to consult to determine their risk of flooding.Even with better maps, knowledge of flood risk can be hampered by weak local awareness.Climate predictions increasingly inform hazard predictions.

Nyc flood last night