Fema flood zones list how to#
Fema flood zones list zip#

| Sources: Flood zones from First Street Foundation, building footprints from Microsoft. Vulnerability to a storm with a 1 percent chance of occurring in a given year. But First Street says the number is almost one-third. According to FEMA’s maps, none of the properties there are in the 100-year floodplain.

Fema flood zones list zip#

One of the Chicago-area ZIP codes with the greatest hidden risk is in Englewood, near the South Side, where almost 95 percent of residents are African-American. The undisclosed risk isn’t always evenly distributed. He said the city’s sewer system is generally intended to withstand rainfall from only a five-year storm, or a storm with 20 percent odds of happening in any given year. The finding that almost 13 percent of Chicago properties are at risk from rain-based flooding “would not surprise me one bit,” said Kevin Fitzpatrick, who supervises sewer infrastructure for the water district. But they agreed that significant flood damage occurs outside the areas marked by FEMA’s flood maps, which are intended to show river-based flooding, rather than flooding caused by heavy rain. Officials with the Metropolitan Water Reclamation District of Greater Chicago, which oversees stormwater management, said they had not reviewed First Street’s work in detail. But according to First Street, almost 13 percent of city properties face that risk - some 75,000 more than FEMA’s maps show. At the top of that list is Chicago.įEMA’s maps show just 0.3 percent of Chicago’s more than 600,000 properties inside the 100-year flood zone. Ashlee Rezin Garcia/Chicago Sun-Times, via Associated Press Inland Cities Face Hidden Risksįirst Street’s calculations indicate that many cities have tens of thousands of properties facing risks not shown on government maps. “The Flood Factor product may help property owners with the critical decisions they must make and purchase necessary insurance.”įlooding along the Chicago River last month. “We know there is no perfect science to predict flooding,” a spokeswoman said. There, the federal maps show more buildings at risk than the new model suggests.įirst Street said that in some areas, including small municipalities, the model may overestimate flood risk because it doesn’t capture every local flood-protection measure, such as pumps or catchment basins.įEMA said it welcomed First Street’s initiative, saying it would “complement FEMA’s efforts.” However, there are exceptions, particularly along the Mississippi River and the Gulf Coast, where the government has more thoroughly studied and planned for floods. Many inland areas, including swaths of Appalachia and numerous major cities, saw big jumps. Overall, the results, which cover the contiguous United States - including areas the government hasn’t yet mapped for flooding, and places where the federal maps are decades old - show a vast increase in risk compared with official estimates. The foundation then checked its results against a national database of flood claims and historic flood paths. The First Street Foundation created its flood model, called Flood Factor, using federal elevation and rainfall data, and coastal flooding estimates from hurricanes. “Millions of home and property owners have had no way of knowing the significant risk they face,” said Matthew Eby, founder and executive director of the First Street Foundation, a group of academics and experts based in New York City who compiled the data, creating a website where people can check their own address. And minority communities often face a bigger share of hidden risk.

In Chicago alone, 75,000 properties have a previously undisclosed flood risk. Numerous cities nationwide - as diverse as Fort Lauderdale, Fla., Buffalo, N.Y., and Chattanooga, Tenn. If the new estimates are broadly accurate, it would mean that homeowners, builders, banks, insurers and government officials nationwide have been making decisions with information that understates their true physical and financial risks.

Fema flood zones list how to#

The federal government’s flood maps guide where and how to build, whether homeowners should buy flood insurance, and how much risk mortgage lenders take on. A 100-year flood is one with a 1 percent chance of striking in any given year. That new calculation, which takes into account sea-level rise, rainfall and flooding along smaller creeks not mapped federally, estimates that 14.6 million properties are at risk from what experts call a 100-year flood, far more than the 8.7 million properties shown on federal government flood maps. Across much of the United States, the flood risk is far greater than government estimates show, new calculations suggest, exposing millions of people to a hidden threat - and one that will only grow as climate change worsens.