Dallas County, Iowa

What hazards hit Dallas County most?

The most frequent records are severe thunderstorm wind events: 350 since 1962. 50% of its severe thunderstorm wind events since 1962 fell in June and July. The rank column places the county among Iowa'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 Dallas County had?

NOAA records 58 tornadoes in Dallas County from 1955 to 2024, the strongest rated F3, with 0 deaths and 2 injuries recorded in the county. That is 6th of 99 Iowa counties and 191st 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 60 tornadoes whose track touched Dallas 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 0 people.

Map of the strongest tornado tracks in Iowa.

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 Dallas County?

The most recent record with damage, injuries or deaths is the May 24, 2024 tornado ($9,408 in damage in 2025 dollars).

Tree damage began along 270th Street between R and S Avenues south of Dallas Center in central Dallas County. The QLCS tornado proceeded east northeast rapidly producing tree damage as well as some outbuilding damage at a farmstead. The tornado passed just south of the Dallas Center/Grimes High School before entering Polk County.
National Weather Service event narrative, NOAA Storm Events Database (search the full record, event 1170127)

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

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 Dallas 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?

50% of its severe thunderstorm wind events since 1962 fell in June and July. The two busiest months are in violet.

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

Federal disaster declarations for Dallas County

FEMA's register lists 20 declarations that include Dallas County: 18 major disasters, 2 emergencies and 0 fire management assistance declarations. Most were for severe storm (9) and flood (6).

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 Dallas County had?

NOAA's Storm Events Database holds 174 flood or flash flood records for Dallas County from 1996 to 2022, on 119 days, with 0 deaths. By flood insurance claims since 1978 (OpenFEMA, as of September 8, 2026), Dallas County ranks 1748th of 2,942 U.S. counties.

The National Flood Insurance Program has paid $639,000 on 42 claims filed in Dallas County; the most in one year was 9 in 2008. 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 Dallas County

FEMA's National Risk Index rates Dallas County Relatively Low overall, with an expected annual loss of $39.7 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 Dallas County

1. Polk County 2,373
2. Dallas County 1,181
3. Warren County 1,065
4. Boone County 806
5. Guthrie County 707
6. Adair County 612
7. Madison County 585
8. Greene County 557

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 IowaEvery Iowa tornado since 1950 and the counties with the most per square mile
• Severe thunderstorm wind in IowaThe state's severe thunderstorm wind events, by county, year and month
• The Iowa recordEvery hazard in the state, its deadliest events and its federal declarations
• FEMA's risk rating for each hazard in Dallas CountyThe hazard risk calculator: 18 hazards beside the county's record
• Download Dallas County's FEMA declarations (CSV)20 rows: every declaration that named the county, for your own analysis