St. Louis County, Missouri

What hazards hit St. Louis County most?

The most frequent records are hail reports: 660 since 1957. 60% of its hail reports since 1957 fell in April and May. The rank column places the county among Missouri's counties by days with a record per 1,000 square miles of land over each hazard's complete period.

Source: NOAA NCEI Storm Events Database (county and forecast-zone records attributed to the county; a zone record shows its own totals on each county it covers). Days: dates with at least one record of the hazard in the county. Ranks: days with a record per 1,000 square miles of land (Census Bureau 2024 Gazetteer), since 1950 for tornadoes, 1955 for hail and thunderstorm wind, 1996 for the rest.

How many tornadoes has St. Louis County had?

NOAA records 58 tornadoes in St. Louis County from 1950 to 2026, the strongest rated EF4, with 15 deaths and 425 injuries recorded in the county. That is 2nd of 114 Missouri counties and 90th of 3,080 U.S. counties by days with tornadoes per 1,000 square miles since 1950. A tornado that crossed a county line is counted in each county it touched, with the length of its path inside the county.

Counted as whole tornadoes rather than county records, the Storm Prediction Center's database holds 57 tornadoes whose track touched St. Louis County since 1950 (NOAA's county records number 58: they file a crossing tornado once per county segment, and the two databases differ on some tracks); along their whole tracks they killed 37 people, 15 of them in St. Louis County.

Map of the strongest tornado tracks in Missouri.

Source: NOAA NCEI Storm Events Database, tornado records by county (path length in the county, maximum width); ratings as published: F scale before February 1, 2007, EF scale after. Whole-track figures: NOAA Storm Prediction Center tornado database (1950-2025). SPC severe weather database.

When was the last damaging storm in St. Louis County?

The most recent record with damage, injuries or deaths is the June 25, 2026 thunderstorm wind ($20,000 in damage in 2025 dollars).

Source: NOAA NCEI Storm Events Database; every record of 2025-2026 is listed, earlier ones when they caused deaths, injuries or $250,000 of damage (2025 dollars), and every tornado.

The deadliest and costliest records

A damage figure marked "step" is a record from before 1993: NOAA then filed damage by category, and the figure is the category as entered, in the dollars of that year, not an estimate of the loss.

Source: NOAA NCEI Storm Events Database: deaths and injuries direct and indirect; damage is property plus crops as estimated by the National Weather Service, converted to 2025 dollars.

Is it getting more frequent?

Records per decade for St. Louis County's most frequent hazards. Counts rose everywhere after 1996, when NOAA began recording every event type, so compare decades within a hazard's complete period only (the shaded cells come before it).

Source: NOAA NCEI Storm Events Database, records per calendar decade; zone records from the CZ_TYPE field (Z).

What time of year?

60% of its hail reports since 1957 fell in April and May. The two busiest months are in violet.

Source: NOAA NCEI Storm Events Database, records by the month they began.

Federal disaster declarations for St. Louis County

FEMA's register lists 34 declarations that include St. Louis County: 25 major disasters, 9 emergencies and 0 fire management assistance declarations. Most were for severe storm (16) and flood (10).

Source: FEMA OpenFEMA Disaster Declarations Summaries (v2), declarations through October 2, 2026; one declaration is counted once however many areas it names. OpenFEMA dataset page.

How many floods has St. Louis County had?

NOAA's Storm Events Database holds 90 flood or flash flood records for St. Louis County from 1996 to 2026, on 84 days, with 7 deaths. By flood insurance claims since 1978 (OpenFEMA, as of September 8, 2026), St. Louis County ranks 44th of 2,942 U.S. counties. The 100 counties with the most claims

The National Flood Insurance Program has paid $265 million on 12,031 claims filed in St. Louis County; the most in one year was 1,967 in 1993. Claims count insured losses only: uninsured flood damage is not in this file.

Source: FEMA OpenFEMA NFIP Redacted Claims, as of September 8, 2026; claims by year of loss, payments in the dollars of the year paid. OpenFEMA dataset page.

FEMA's modeled risk for St. Louis County

FEMA's National Risk Index rates St. Louis County Relatively High overall, with an expected annual loss of $753 million. These are FEMA's model estimates of future loss from 18 hazards, not a count of what happened; they can differ from the record above.

Source: FEMA National Risk Index, county table, December 2025 release. FEMA's National Risk Index map.

Counties that share a border with St. Louis County

1. St. Louis County 1,651
2. St. Clair County, IL 1,047
3. Madison County, IL 1,009
4. St. Charles County 995
5. Franklin County 882
6. Jefferson County 805
7. St. Louis (city) 472
8. Monroe County, IL 451

Source: U.S. Census Bureau county adjacency file; NOAA NCEI Storm Events Database, records since 1950. The Census Bureau's adjacency file.

Next

• Tornadoes in MissouriEvery Missouri tornado since 1950 and the counties with the most per square mile
• Hail in MissouriThe state's hail reports, by county, year and month
• The Missouri recordEvery hazard in the state, its deadliest events and its federal declarations
• FEMA's risk rating for each hazard in St. Louis CountyThe hazard risk calculator: 18 hazards beside the county's record
• Download St. Louis County's FEMA declarations (CSV)34 rows: every declaration that named the county, for your own analysis