Natural hazard guides
How to read natural hazard risk reports and the record behind them: what FEMA's risk scores and flood zones mean, how tornadoes are rated, which federal database counts what, and what the record says about risk by region and over time. Every figure is computed from the same data as the county pages: 2,004,972 NOAA storm records through June 30, 2026 and FEMA declarations through October 2, 2026.
Reading risk reports
- Tornado Alley, measuredWhich states it covers by the record, with maps of two eras
- How to read FEMA risk scoresThe National Risk Index score, rating and its fields
- How to read a FEMA flood mapFlood zones A, V and X, shaded and unshaded
- The Enhanced Fujita scaleHow tornadoes are rated, and how many of each
- The disaster databases, explainedFEMA and NOAA: what each one counts
Risk by place and time
Source: NOAA NCEI Storm Events Database (through June 30, 2026), NOAA Storm Prediction Center tornado database (to 2025), FEMA OpenFEMA (through October 2, 2026); each page names its own files and dates.