Interactive tool · FEMA + NOAA data
Historical Disaster Activity Index
Compare any U.S. state or county on a disclosed 0–100 historical-activity index. State scores use FEMA declarations and NOAA event and damage history; county scores use FEMA declaration frequency, density, Major Disaster share, and declared-hazard diversity. See our methodology.
This index scores historical FEMA/NOAA activity, not current risk. In an active emergency, call 911. For current watches, warnings, and advisories, follow the National Weather Service and local officials.
About this calculator
This calculator draws on all 59 U.S. states and territories in PlainHazard's database, benchmarking each location against a national average of 88 FEMA declaration records per state. Its PlainHazard score sorts historical activity into Low, Moderate, High, or Very High bands; it is neither FEMA's National Risk Index nor a predictive model.
- 59
- states and territories you can score
- 88
- FEMA declarations, the national per-state average
- 4
- activity bands: Low, Moderate, High, Very High
Pick a state above to see its full breakdown across all four scored factors.
States with the most FEMA declarations
Total FEMA disaster declarations, pick any state above to score it
- California
California
396 declarations
- Texas
Texas
389 declarations
- Oklahoma
Oklahoma
258 declarations
- Washington
Washington
215 declarations
- Florida
Florida
188 declarations
- Oregon
Oregon
169 declarations
- New Mexico 126
New Mexico
126 declarations
- Arizona 120
Arizona
120 declarations
- New York 118
New York
118 declarations
- Montana 112
Montana
112 declarations
What this shows California records the most FEMA declaration records of any state. Select a state or county to see PlainHazard's disclosed 0–100 historical-activity score.
What you'll get
- 0–100 PlainHazard historical-activity score
- 4 scored factors with a per-factor breakdown
- 18 FEMA hazard types ranked for your county
- Rank your county vs neighbors by NRI risk score
- ↗ shareable link to your county's profile
How the historical-activity score works
A disclosed 0–100 historical-activity index built from four factors. State scores use FEMA declarations plus statewide NOAA frequency and damage; county scores use declaration frequency, state-relative declaration density, Major Disaster share, and declared-hazard diversity because county-level NOAA damage is not in this database. This is PlainHazard's own index, not FEMA's National Risk Index. See the exact weights in the breakdown above and our methodology.
30 pts
FEMA Declarations
Disaster declaration count relative to national averages.
25 pts
Storm Events
NOAA severe-weather event frequency versus the median state.
25 pts
Property Damage
Total property and crop damage versus the national median.
20 pts
Hazard Diversity
How many different disaster types have been declared in the area.
Frequently Asked Questions
How is the historical-activity score calculated?
The state score combines FEMA declaration frequency (30 points), NOAA storm-event frequency (25), NOAA property and crop damage (25), and declared-hazard diversity (20). County rows do not contain county-level NOAA damage in this database, so the county score instead uses FEMA declaration frequency (30), declaration density versus the state county average (25), Major Disaster share (25), and declared-hazard diversity (20). PlainHazard labels both as derived historical indexes, not FEMA National Risk Index scores.
What data sources are used?
The calculator uses FEMA OpenFEMA declaration records (1953–2026) for state and county scores. State scores also use NOAA Storm Events records (2015–2025); county scores do not because this database has no county-level NOAA damage. FEMA and NOAA publish the source records; the weighted score is PlainHazard-derived.
What does the historical-activity band mean?
Low (0-24), Moderate (25-49), High (50-74), and Very High (75-100) compare the recorded factors used by this tool. They describe relative historical activity, not future hazard probability, a FEMA risk rating, or a safety forecast.
Can I compare historical activity for a specific county?
Yes. Select a state first, then optionally select a county to see its historical declaration record and FEMA National Risk Index context. PlainHazard scores use FEMA declarations for that county compared with national and state averages.
How often is the data updated?
The underlying database includes FEMA declarations through 2026 and NOAA storm events through 2025. PlainHazard scores reflect the historical record available from each source and do not predict future events.
How to use this
This score is a historical-data summary, not a prediction, use it as a starting point for further research, not a final verdict on any one place.
- Score your state first to set a national baseline, then narrow to a specific county for localized detail. Browse states
- A low county score does not guarantee low risk, rare but severe hazards (a single major hurricane or earthquake) can score low on this 2015-2025 window while still posing real long-run exposure.
- FEMA's National Risk Index, official local hazard maps, and current emergency guidance are separate sources; this retrospective index contains none of their real-time or predictive signals. Read the methodology
This historical-activity score is PlainHazard's own derived index, weighted and combined from federal source data. It is not FEMA's National Risk Index or an official government rating.
Data sources: FEMA OpenFEMA Disaster Declarations (1953–2026), NOAA Storm Events Database, NFIP Flood Insurance Claims. Historical-activity scores are computed by PlainHazard and do not predict future events. This tool is for informational purposes only.
PlainHazard calculates this historical-activity score from federal source data covering 3,266 U.S. counties and county equivalents in this database, refreshed as of 2026-08-25. FEMA does not publish or endorse this score. Read our methodology for how the score is computed.
Every figure on PlainHazard is rendered directly from FEMA federal disaster data, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or national statistics report, the data & editorial changelog, or report a data error.