Black Hawk County, Iowa

What hazards hit Black Hawk County most?

The most frequent records are severe thunderstorm wind events: 271 since 1956. 56% of its severe thunderstorm wind events since 1956 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 Black Hawk County had?

NOAA records 39 tornadoes in Black Hawk County from 1960 to 2020, the strongest rated F4, with 2 deaths and 79 injuries recorded in the county. That is 40th of 99 Iowa 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 40 tornadoes whose track touched Black Hawk County since 1950 (NOAA's county records number 39: they file a crossing tornado once per county segment, and the two databases differ on some tracks); along their whole tracks they killed 12 people, 2 of them in Black Hawk County.

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 Black Hawk County?

The most recent record with damage, injuries or deaths is the February 19, 2026 heavy snow (1 injury).

A surface low lifted into the central US with a deformation zone setting up across central Iowa, resulting in a band of heavy snow bisecting the state. Light precipitation fell ahead of the main deformation zone, however dry air and warm temperatures meant this largely fell as rain to start. The main deformation zone set up across Iowa in the afternoon with rain transitioning over to snow and temperatures fell. Heaviest snow fell through the overnight with rates over one inch per hour at times. Snow tapered off quickly through the morning hours. Roads across central Iowa were snow covered with impacts to the morning commute on the 20th, including an accident with injury. Operations were also paused overnight at the Des Moines airport.
National Weather Service event narrative, NOAA Storm Events Database (search the full record, event 1322490)

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 Black Hawk 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?

56% of its severe thunderstorm wind events since 1956 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 Black Hawk County

FEMA's register lists 20 declarations that include Black Hawk County: 18 major disasters, 2 emergencies and 0 fire management assistance declarations. Most were for flood (9) and severe storm (8).

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 Black Hawk County had?

NOAA's Storm Events Database holds 202 flood or flash flood records for Black Hawk County from 1996 to 2025, on 133 days, with 0 deaths. By flood insurance claims since 1978 (OpenFEMA, as of September 8, 2026), Black Hawk County ranks 248th of 2,942 U.S. counties.

The National Flood Insurance Program has paid $27.3 million on 1,472 claims filed in Black Hawk County; the most in one year was 416 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 Black Hawk County

FEMA's National Risk Index rates Black Hawk County Relatively Low overall, with an expected annual loss of $41.8 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 Black Hawk County

1. Black Hawk County 1,062
2. Benton County 989
3. Buchanan County 822
4. Butler County 734
5. Fayette County 634
6. Tama County 625
7. Bremer County 583
8. Grundy County 558

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 Black Hawk CountyThe hazard risk calculator: 18 hazards beside the county's record
• Download Black Hawk County's FEMA declarations (CSV)20 rows: every declaration that named the county, for your own analysis