Every number on this site comes from public government data. Here is how we use it.
The data
- Tornadoes: NOAA Storm Prediction Center (SPC) Severe Weather Database, 1950 to 2024, including state and county segments. 71,808 tornadoes.
- Risk: FEMA National Risk Index, tornado layer (December 2025 release).
- Maps: U.S. Census Bureau county boundaries (via the us-atlas project).
How we count
- A tornado counts for a county if the SPC lists that county for it. The database lists up to four counties per state segment, so a very long track can miss a county.
- State totals follow SPC practice: a tornado that crosses a state line counts in each state, so state totals add up to slightly more than the national total.
- Deaths and injuries on county pages are for each tornado’s whole path.
- Ratings: F scale before February 1, 2007; EF scale after; EF-U means not rated.
- Tracks on the maps are straight lines from touchdown to lift-off; real paths curve.
What we do not do
- We do not predict tornadoes or say any place is safe.
- We do not invent risk scores: the only risk rating shown is FEMA’s.
Sources
- NOAA Storm Prediction Center: Severe Weather Database, tornadoes 1950 to 2024 (public domain)
- FEMA National Risk Index, tornado county data (December 2025 release)
- NOAA Storm Prediction Center: The Enhanced Fujita Scale (EF scale)
- National Weather Service: Tornado safety
- National Weather Service: Understanding watches and warnings
- Ready.gov: Tornadoes
- FEMA P-320, Taking Shelter from the Storm (2024 edition, PDF)
- National Storm Shelter Association: residential tornado shelters (3 sq ft per person for one- and two-family dwellings)
- FEMA: Safe rooms
- National Weather Service: NOAA Weather Radio All Hazards
- NOAA Storm Prediction Center: Tornado climatology (FAQ)
Sources last checked 1 November 2026.