Updated May 2026
Flood Risk Trend Reports
Data-driven reports tracking where flood loss is accelerating, which counties have absorbed the most NFIP payouts, and how the riskiest tier of U.S. counties is shifting over time. Every report is rebuilt from the latest FEMA NFIP claim and disaster-declaration data — covering 3,277 counties, 99,729 flood-insurance claims, and 1,403 federal disaster declarations to date.
What These Reports Track
Each report is an aggregate view across the four-factor flood risk score — claims density (40%), disaster frequency (25%), claim severity (20%), and year-over-year trend (15%). Reports surface the steepest movers (counties whose grade or score has shifted), the heaviest-loss counties (largest NFIP payouts), and the longest-running disaster cadence (counties with the most declarations on file). The full scoring formula is on the methodology page; the underlying source datasets are FEMA's public OpenFEMA API plus complementary hydrology context from USGS Water Data and NOAA storm-surge guidance.
National Snapshot
Where Loss Is Concentrated
Flood risk is sharply concentrated. Although 3,277 counties carry a flood score, only 0% sit at an F grade — the extreme-risk tier — and another large slice of the dataset (the A grade) sees almost no measurable insured loss in any given year. The top-10 riskiest counties span just a handful of states (TX, FL, LA), reflecting how Gulf Coast, lower-Mississippi, and Atlantic-coast geography concentrates both storm exposure and NFIP take-up. Browse the full state-by-state breakdown or the riskiest-counties ranking to drill in.
Top 5 Riskiest Counties Right Now
| # | County | State | Grade | Score | Claims |
|---|---|---|---|---|---|
| 1 | Harris | TX | D | 74 | 12K |
| 2 | Lee | FL | C | 60 | 6.2K |
| 3 | Pinellas | FL | C | 55 | 4.9K |
| 4 | Jefferson | LA | B | 40 | 913 |
| 5 | Collier | FL | B | 39 | 2.0K |
Trend Reports
Highest Flood Risk Counties
Counties with the worst flood risk scores in America
Most FEMA Flood Claims
Counties with the highest number of flood insurance claims
How These Trends Are Built
Trends combine two FEMA OpenFEMA endpoints. The DisasterDeclarationsSummaries v2 endpoint provides every federally declared disaster, filtered to flood-related incident types (flood, hurricane, severe storm, coastal storm, typhoon). The FimaNfipClaims endpoint provides individual NFIP flood-insurance claims aggregated by county FIPS code. Year-over-year trend slope is computed from the claims series and contributes 15% of each county's composite risk score. We refresh on a recurring cadence; full caveats are listed under "Limitations" on the methodology page.
Frequently Asked Questions
What goes into a flood risk trend report?
Each trend report aggregates the OpenFEMA datasets — disaster declarations and NFIP claims — and surfaces the largest movers, the most-claims counties, and the steepest rising trend lines. Reports are recomputed every refresh and cover 3,277 counties and 1,403 federally declared disasters.
Where is U.S. flood loss concentrated right now?
0% of U.S. counties carry a D or F flood-risk grade, with 0% scored F. The riskiest tier is dominated by Gulf Coast and lower-Mississippi states (top-10 examples include TX, FL, LA). NFIP payouts have totaled $5,984,054,651 across the dataset.
How often is the trend data refreshed?
The pipeline pulls fresh OpenFEMA data through the public API on a recurring cadence; FEMA itself republishes NFIP claims roughly every quarter, so the freshest reports here lag actual events by up to three months. The current dataset was last updated on 2026-05-16.
How are flood risk scores calculated for these reports?
Every county gets a 0–100 composite score: 40% claims density, 25% disaster frequency, 20% claim severity, and 15% year-over-year trend. Letter grades A–F bucket the score for fast comparison. The full formula and limitations are documented on the methodology page.
Where can I verify these numbers against the original FEMA data?
Every datapoint is sourced from FEMA OpenFEMA (the DisasterDeclarationsSummaries v2 endpoint and the FimaNfipClaims endpoint). Both are public-domain and queryable directly. The EPA-style flood-map context behind FEMA designations lives at fema.gov/flood-maps; real-time hydrology context comes from USGS Water Data.
Flood risk trend reports built from FEMA OpenFEMA data covering 3,277 U.S. counties and 1,403 disaster declarations.