New Data Shows Flood Risk In NYC Is More Than Previously Expected

NEW YORK CITY – A new report from the First Street Foundation provides a national analysis of flood risk in states and cities across the United States, including in New York City.

The nonprofit, dedicated to the research and development of flood prevention, released a model that allows users to assess flood risk in the past, present and future at the individual property level by location. The risk assessment takes into account sea-level rise, rainfall and flooding along smaller bodies of water.

The new in-depth report estimates that 14.6 million properties across the United States are at substantial risk of flooding, which is a staggering 5.9 million more properties than the Federal Emergency Management Agency (FEMA) shows on federal government flood maps.

First Street uses three risk description levels to classify the chances of flooding in an area:

• Almost certain risk: 20 percent annual probability
• Substantial risk: 1 percent annual probability
• Any risk: 0.2 percent annual probability

Here’s the risk of flooding in New York City, according to the First Street Foundation.

• Total properties at substantial risk in 2020: 73,490
• Total properties at substantial risk in 2050: 88,338
• Difference in the number of properties currently at substantial risk compared to FEMA maps: +14,848

New York City will see the most significant increase in flood risk over the next 30 years in the state, according to the data.

The city of New York has the greatest number of properties at risk of flooding in the state with 121,200 currently at risk, or 14% of its total number of properties.

In 2012, Hurricane Sandy affected 120,517 properties, according to the data. Other flooding events since 2000 are as follows:

• Feb. 2003: Nor'easter, 1,647 properties affected
• Nov. 2009: Nor'easter, 20,641 properties affected
• Mar. 2010: Nor'easter, 1,870 properties affected
• Aug. 2011: Hurricane Irene, 35,716 properties affected

You can use the nonprofit’s new Flood Factor tool to check the flood risk of your exact address.

While the data from First Street shows that flood risk in the nation is much higher than FEMA’s estimates, the government agency welcomes the new data from the nonprofit.

“We know there is no perfect science to predict flooding,” a FEMA spokesperson told the New York Times. “The Flood Factor product may help property owners with the critical decisions they must make and purchase necessary insurance.”

Additionally, FEMA’s maps don’t take into consideration flooding caused by intense rainfall, which First Street’s model does.

The First Street Foundation’s new report was made in collaboration with more than 80 scientists, technologists and experts, as well as in partnership with researchers from Columbia University, George Mason University, Massachusetts Institute of Technology and others.

You can read more about the methodology of the nonprofit’s report on its website.

In 2020, Cape Coral, Florida, has the greatest number of properties at substantial risk of any city in the United States. The rest of the top five is rounded out by Los Angeles, California, Chicago, Illinois, Houston, Texas, and New York, New York.

The full “First National Flood Risk Assessment” report is available on First Street’s website.