2024’s Counties Most at Risk for Flooding

Hurricane Ian flooded houses in Florida residential area.

Which parts of the U.S. are most vulnerable to flood damage?

To mark the start of flood season (June to Nov.), LawnStarter ranked 2024’s Counties Most at Risk for Flooding.

We compared over 940 counties with a relatively moderate to very high flood risk according to FEMA. We considered each county’s risk and expected annual loss from riverine and coastal flooding. We also looked at the share of populations of children, elderly, and residents in mobile homes, in addition to local demand for flood insurance. 

See where your county landed in our ranking below. To learn how we ranked the counties, see our methodology.

Contents

County Rankings

See how each county fared in our ranking:

Top 5 Close Up

Check out the slideshow below for a closer look at each of our 5 counties with the highest flood risk.

Families canoe down flooded streets in Houston
No. 1: Harris County, Texas | 3 Biggest Cities: Houston, Pasadena, Pearland

Overall Score: 63.87
Riverine Flooding Risk Score: 100 | Rank: 1
Coastal Flooding Risk Score: 73.84 | Rank: 131
Expected Annual Loss from Riverine Flooding: $676.2 million | Rank: 1
Expected Annual Loss from Coastal Flooding: $829,391 | Rank: 142
Average Monthly Google Searches for Terms Related to Flood Insurance: 880 | Rank: 1

Photo Credit: Irina K. / Adobe Stock / License
A view of Bergen County, New Jersey, from across the river
No. 2: Bergen County, New Jersey | 3 Biggest Cities: Hackensack, Fort Lee, Fair Lawn

Overall Score: 60.98
Riverine Flooding Risk Score: 95.16 | Rank: 153
Coastal Flooding Risk Score: 100 | Rank: 1
Expected Annual Loss from Riverine Flooding: $7.4 million | Rank: 132
Expected Annual Loss from Coastal Flooding: $210.4 million | Rank: 1
Average Monthly Google Searches for Terms Related to Flood Insurance: 70 | Rank: 40

Photo Credit: PunkToad / Flickr / CC BY 2.0
Flooded houses collapse along the beach in Ocean County, New Jersey
No. 3: Ocean County, New Jersey | 3 Biggest Cities: Toms River, Lakewood, Point Pleasant

Overall Score: 57.67
Riverine Flooding Risk Score: 98.09 | Rank: 61
Coastal Flooding Risk Score: 99.6 | Rank: 3
Expected Annual Loss from Riverine Flooding: $22 million | Rank: 37
Expected Annual Loss from Coastal Flooding: $100.5 million | Rank: 2
Average Monthly Google Searches for Terms Related to Flood Insurance: 50 | Rank: 57

Photo Credit: U.S. Fish and Wildlife Service Northeast / Flickr / Public Domain
People walk down a flooded street in Atlantic City, New Jersey
No. 4: Atlantic County, New Jersey | 3 Biggest Cities: Vineland, Atlantic City, Glassboro

Overall Score: 53.58
Riverine Flooding Risk Score: 97.55 | Rank: 78
Coastal Flooding Risk Score: 99.8 | Rank: 2
Expected Annual Loss from Riverine Flooding: $11.2 million | Rank: 84
Expected Annual Loss from Coastal Flooding: $77.5 million | Rank: 3
Average Monthly Google Searches for Terms Related to Flood Insurance: 20 | Rank: 132

Photo Credit: Diariocritico de Venezuela / Flickr / CC BY 2.0
A newspaper stand is toppled over in standing water on a flooded street in Ocean City, New Jersey
No. 5: Cape May County, New Jersey | 3 Biggest Cities: Ocean City, Villas, Cape May Court House

Overall Score: 52.43
Riverine Flooding Risk Score: 92.43 | Rank: 239
Coastal Flooding Risk Score: 99.4 | Rank: 4
Expected Annual Loss from Riverine Flooding: $5 million | Rank: 204
Expected Annual Loss from Coastal Flooding: $64.7 million | Rank: 4
Average Monthly Google Searches for Terms Related to Flood Insurance: 10 | Rank: 189

Photo Credit: Scott Brandon Peterson / Flickr / CC BY 2.0

Key Insights

  • Gulf Coast states Florida, Louisiana, and Texas account for nearly half of the 100 most vulnerable counties to flooding. Counties in Texas and Louisiana anticipate among the highest economic impacts from riverine flooding, often caused by hurricanes or tropical storms.  
  • Counties in Mid-Atlantic states like New Jersey, New York, and Virginia also face among the highest flood risk. 6 Garden State counties scored among the 10 counties with the highest overall Economic Impact from coastal and riverine flooding. 
  • Geologic changes are just one element exacerbating flooding during storms along the mid-Atlantic coast. Research shows much of New York (No. 64), Baltimore (No. 255), and Norfolk, Virginia (No. 39), sank by about 1-2 millimeters between 2007 and 2020. 
  • All counties in our ranking have at least relatively moderate flood risk, according to FEMA. Less populated counties in Upstate New York, like Warren (No. 939) and Livingston (No. 941) landed near the bottom alongside Tompkins County, in last place. These counties have more moderate flood risks and with smaller populations, lower economic impact from flooding.

Learn more about regional flooding stats below.

Methodology

First, we determined the factors (metrics) that are most relevant to rank the Counties Most at Risk for Flooding. We then assigned a weight to each factor based on its importance and grouped those factors into 4 categories: Flood Risk, Economic Impact, Preparedness, and Population Vulnerability. The categories, factors, and their weights are listed in the table below.

For each of the 943 counties with a relatively moderate to very high risk of coastal and/or riverine flooding according to FEMA, we then gathered data on each factor from the sources listed below the table. 

Finally, we calculated scores (out of 100 points) for each county to determine its rank in each factor, each category, and overall. A county’s Overall Score is the average of its scores across all factors and categories. The highest Overall Score ranked “Best” (No. 1) and the lowest “Worst” (No. 943).

  • The “Worst” among individual factors may not be No. 943 due to ties.
  • Some counties in our ranking identify by a different geographical term. Baltimore City, Maryland, for example, operates as both a city and county separately from Baltimore County, Maryland. In Louisiana, counties are known as “parishes.”
  • Coastal Flood Risk — calculated by FEMA — considers the annualized frequency of and exposure to coastal floods as well as social vulnerability and community resilience factors.
  • Riverine Flood Risk — calculated by FEMA — considers the annualized frequency of and exposure to riverine floods as well as social vulnerability and community resilience factors.
  • Coastal Flooding Expected Annual Loss — calculated by FEMA — measures the financial impact of expected annual building and population loss due to coastal floods.
  • Riverine Flooding Expected Annual Loss — calculated by FEMA — measures the financial impact of expected annual building and population loss due to riverine floods.

Sources: Federal Emergency Management Agency, FloodSmart.gov, Google Ads, and U.S. Census Bureau

Final Thoughts: Community Flood Control 

Flooding accounts for two-thirds of damage costs from all natural disasters in the U.S.

With sea levels rising, coastal cities sinking, and dams and levees aging, flood events may become even more frequent and destructive

2023 had historic rainfall and flooding events across the country, from Southern California to Vermont. Since many people are drawn to coastal and riverside living, floodplain populations continue to grow despite increasing environmental risks. Today, over half of Americans reside in an area with 2X the risk of experiencing a 100-year flood.

With an urban flooding event impacting U.S. cities every 2 to 3 days over the last 25 years, urban stormwater systems are struggling to keep up with early and extreme snowmelt, higher precipitation rates, and stronger hurricanes

U.S. cities generate so much stormwater runoff each year that it could supply 93% of the nation’s municipal and industrial water usage. Stormwater infrastructure upgrades and natural flood mitigation responses — like stormwater ponds, beach nourishment, and floodplain preservation and restoration — can help reduce urban flooding impacts and recharge drought-stricken aquifers.

Only 4% of U.S. homeowners are protected by flood insurance. Flood insurance can be a worthwhile investment, even for homeowners who don’t live in a designated flood zone. 

Take other steps to protect your property from flood damage and help it recover after a flood with help from our guides below. 

Hire a local LawnStarter crew to help clean up and restore your lawn after a flood event.

Media Resources

  • Statistics show that most Hurricane Harvey victims were uninsured. Residents of Harris County, Texas (No. 1), home to Houston, demonstrate the highest demand for flood insurance. Houston is one of the fastest-sinking cities in the world. 
  • Counties in Florida like Dixie (No. 12) and Putnam (No. 80) have among the highest flooding risk and high shares of residents who are elderly or living in mobile homes.
  • Florida has the best access to flood insurance providers, with 31. However, only 13% of Sunshine State residences are insured against flooding. The state is trying to develop a more resilient coast with projects like living shorelines
  • 4 coastal Oregon countiesCoos (No. 13), Douglas (No. 35), Clatsop (No. 38), and Tillamook (No. 50) — stand out as the only Pacific Coast counties among the 50 most vulnerable counties for flooding. 
  • Horry County, South Carolina (No. 21), is home to Charleston, another rapidly sinking city. Locals are fighting for wetland conservation and more flood-resistant building codes.
  • Inland counties with the greatest risk of riverine flooding include Shelby County, Tennessee (No. 328), Washoe County, Nevada (No. 339), and Davidson County, Tennessee (No. 394) — home to Memphis, Reno, and Nashville, respectively. 
  • Subsidence and rising sea levels are poisoning trees with saltwater — accelerating tree loss and creating ghost forests along the Atlantic, Pacific, and Gulf coasts, and in Alaska. 

Main Photo Credit: Hurricane Ian flooded houses in Florida residential area: bilanol / Adobe Stock / License

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Sav Maive

Sav Maive is a writer and director based in San Antonio. Sav is a graduate of the University of Virginia and is a loving cat and plant mom.