Cerro Gordo County, Iowa

County storm and disaster record · FIPS 19033 · population 43,117 · 568 sq mi

NOAA's Storm Events Database holds 854 records for Cerro Gordo County, Iowa from 1950 through June 30, 2026, on 515 days; the most frequent are severe thunderstorm wind events (223 records). The deadliest single record is the July 7, 1991 thunderstorm wind: 1 death. FEMA has issued 15 declarations naming the county since 1965, 13 of them for natural hazards; the latest for a natural hazard was “Severe Storms, Tornadoes, Straight-Line Winds, and Flooding” on August 20, 2018.

The record, 1950 to 2026

Storm records filed for the county each year (2026 to June 30, 2026). Before 1996 NOAA recorded only tornadoes (from 1950), thunderstorm wind and hail (from 1955).

  • recorded, no damage figure
  • under $100,000
  • $100,000 or more
  • $1 million or more
  • $10 million or more, or a death
  • $100 million or more, or 10 deaths
  • a year's colour: its recorded damage or deaths
  • a year with a death
  • 1955: wind and hail recorded from 1955
  • 1996: all 48 event types from 1996
Storm records
854on 515 days, 1950 to June 30, 2026
Deaths recorded
115 injuries
Damage, 2025 dollars
$186Mas filed (scale steps before 1993)
Tornadoes
39strongest F4
FEMA declarations
15latest 2020

Source: NOAA NCEI Storm Events Database, records through June 30, 2026 (file revision 20260918); damage converted to 2025 dollars with the BLS CPI-U. Search the record at NCEI. BLS consumer price index.

What hazards hit Cerro Gordo County most?

The most frequent records are severe thunderstorm wind events: 223 since 1956. 54% 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.

Cerro Gordo County: records by hazard, 1950 to June 30, 2026
HazardRecordsDaysFirst, lastKilledInjuredDamageRank in state
Severe thunderstorm wind 223 134 1956-2025 1 11 $4.9M 17 of 99
Hail 184 91 1959-2025 0 0 $1.9M 35 of 99
Winter storms 105 102 1996-2025 0 0 $2.7M 42 of 99
Floods 82 63 1997-2024 0 0 $42M 29 of 99
Heavy rain 76 32 2007-2024 0 0 – 20 of 99
High wind and dust storms 55 53 1996-2025 0 1 $3.2M 7 of 99
Tornadoes 39 31 1953-2025 0 3 $16M 31 of 99
Extreme cold 38 38 1996-2025 0 0 $9.4M 13 of 99
Drought 24 24 2001-2024 0 0 $105M 62 of 99
Fog, smoke and funnel clouds 14 11 1996-2021 0 0 – 32 of 99
Lightning 10 10 1997-2019 0 0 $241K 8 of 99
Heat 4 4 2001-2019 0 0 $177K 62 of 99

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 Cerro Gordo County had?

NOAA records 39 tornadoes in Cerro Gordo County from 1953 to 2025, the strongest rated F4, with 0 deaths and 3 injuries recorded in the county. That is 31st 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 Cerro Gordo 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 0 people.

The deadliest and strongest tornadoes that touched Cerro Gordo County, whole tracks
DateTornadoRatingPathKilled
1953-05-10 16:10, as SPC files itVentura to FertileF426.6 mi0
1967-04-30 17:05, as SPC files itClear LakeF37.7 mi0

Map of the strongest tornado tracks in Iowa.

Every tornado record filed for Cerro Gordo County (39)
Every tornado recorded in Cerro Gordo County, newest first
DatePlaceCharacterKilledInjuredDamage
2025-07-28 Clear Lake, Cerro Gordo County EF0 1.64 mi x 15 yd 0 0 –
2022-04-12 Clear Lake Jct, Cerro Gordo County EF1 4.49 mi x 100 yd 0 0 $126K
2021-12-15 Rock Falls, Cerro Gordo County EF0 3.54 mi x 60 yd 0 0 $545
2021-12-15 Rockwell, Cerro Gordo County EF0 2.86 mi x 40 yd 0 0 $545
2021-12-15 Meservey, Cerro Gordo County EF2 4.93 mi x 100 yd 0 0 $109K
2021-08-27 Dougherty, Cerro Gordo County EFU 2.04 mi x 110 yd 0 0 $2K
2021-08-27 Clear Lake, Cerro Gordo County EF0 2.14 mi x 250 yd 0 0 $2K
2021-07-14 Rockwell, Cerro Gordo County EF0 5.1 mi x 225 yd 0 0 $13K
2018-06-09 Clear Lake Lake, Cerro Gordo County EF0 1.18 mi x 30 yd 0 0 $235
2014-06-16 Freeman, Cerro Gordo County EF0 1.1 mi x 40 yd 0 0 $9K
2014-06-16 Mason City Municipal, Cerro Gordo County EF1 3.03 mi x 110 yd 0 0 $74K
2008-06-07 Mason City Municipal, Cerro Gordo County EF0 1.01 mi x 40 yd 0 0 $7K
2005-07-03 Rock Falls, Cerro Gordo County F0 0.1 mi x 25 yd 0 0 $2K
2005-03-30 Mason City, Cerro Gordo County F0 1.1 mi x 50 yd 0 0 –
2005-03-30 Mason City, Cerro Gordo County F0 0.5 mi x 40 yd 0 0 –
2005-03-30 Mason City, Cerro Gordo County F0 0.2 mi x 30 yd 0 0 –
2004-04-17 Mason City, Cerro Gordo County F0 0.2 mi x 25 yd 0 0 –
2003-07-04 Mason City, Cerro Gordo County F0 0.1 mi x 20 yd 0 0 –
2002-06-21 Rockwell, Cerro Gordo County F1 5 mi x 40 yd 0 0 $8K
1999-08-09 Burchinal, Cerro Gordo County F0 0.1 mi x 25 yd 0 0 –
1999-06-06 Mason City, Cerro Gordo County F0 0.1 mi x 20 yd 0 0 –
1998-06-27 Swaledale, Cerro Gordo County F2 12.5 mi x 50 yd 0 0 $244K
1998-06-27 Thornton, Cerro Gordo County F2 7.5 mi x 50 yd 0 0 $94K
1995-06-06 Mason City Airport, Cerro Gordo County F1 3.5 mi x 40 yd 0 0 $149K
1994-07-06 Portland To, Cerro Gordo County F1 11.5 mi x 30 yd 0 0 $110K
1992-05-16 Cerro Gordo County F0 0.2 mi x 20 yd 0 0 $25K step
1990-08-02 Cerro Gordo County F1 3 mi x 33 yd 0 0 $25K step
1988-03-24 Cerro Gordo County F1 1 mi x 20 yd 0 0 $250K step
1984-06-22 Cerro Gordo County F1 9 mi x 77 yd 0 0 $2.5M step
1984-06-16 Cerro Gordo County F1 6 mi x 77 yd 0 2 $250K step
1980-05-30 Cerro Gordo County F1 1 mi x 30 yd 0 0 $25K step
1980-05-29 Cerro Gordo County F2 0.5 mi x 30 yd 0 0 $25K step
1979-08-28 Cerro Gordo County F1 1 mi x 60 yd 0 0 $25K step
1977-02-23 Cerro Gordo County F1 0.1 mi x 13 yd 0 1 $250K step
1973-09-26 Cerro Gordo County F2 2 mi x 100 yd 0 0 $25K step
1967-04-30 Cerro Gordo County F3 7.7 mi x 250 yd 0 0 $250K step
1960-08-28 Cerro Gordo County F1 1 mi x 200 yd 0 0 $3K step
1960-08-28 Cerro Gordo County F1 1 mi x 200 yd 0 0 $3K step
1953-05-10 Cerro Gordo County F4 20.2 mi x 33 yd 0 0 $250K step

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, 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 Cerro Gordo County?

The most recent record with damage, injuries or deaths is the July 28, 2025 thunderstorm wind ($50,000 in damage in 2025 dollars).

The 12 most recent records kept for Cerro Gordo County
DateRecordCharacterKilledInjuredDamage
2025-09-16 HailSwaledale, Cerro Gordo County 1.00 in hail 0 0 –
2025-08-06 High WindCerro Gordo County · forecast zone Cerro Gordo 52 kt wind 0 0 –
2025-07-28 Thunderstorm WindVentura, Cerro Gordo County 61 kt wind 0 0 $50K
2025-07-28 Thunderstorm WindVentura, Cerro Gordo County 56 kt wind 0 0 $10K
2025-07-28 TornadoClear Lake, Cerro Gordo County EF0 1.64 mi x 15 yd 0 0 –
2025-07-27 Thunderstorm WindRock Falls, Cerro Gordo County 58 kt wind 0 0 $10K
2025-07-27 Thunderstorm WindMason City, Cerro Gordo County 62 kt wind 0 0 $20K
2025-07-27 Thunderstorm WindMason City Municipal, Cerro Gordo County 62 kt wind 0 0 –
2025-06-20 HailMason City Municipal, Cerro Gordo County 1.00 in hail 0 0 –
2025-06-20 Thunderstorm WindMason City Municipal, Cerro Gordo County 51 kt wind 0 0 –
2025-04-28 HailMason City, Cerro Gordo County 0.88 in hail 0 0 –
2025-04-28 HailVentura, Cerro Gordo County 1.00 in hail 0 0 –

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

Records with deaths or injuries in Cerro Gordo County, most deaths first
DateRecordCharacterKilledInjuredDamage
1991-07-07 Thunderstorm WindCerro Gordo County 1 0 –
1997-06-15 Thunderstorm WindClear Lake, Cerro Gordo County Thunderstorms developed to the north of Iowa with the tail of a line of thunderstorms brushing into north central Iowa. As the storms moved into Clear Lake, high winds downed trees across the city. Four injuries were reported due to falling tree debris. 0 4 $74K
2007-08-15 Thunderstorm WindSwaledale, Cerro Gordo County Two semis were blown over between mile markers 185 and 186 on interstate 35. 61 kt wind 0 2 $85K
1984-06-16 TornadoCerro Gordo County F1 6 mi x 77 yd 0 2 $250K step
2018-08-28 Thunderstorm WindThornton, Cerro Gordo County Law enforcement reported a semi-truck blown over by winds on Interstate 35. One individual was transported to the hospital. Time estimated from radar. 56 kt wind 0 1 $35K
2003-11-12 High WindCerro Gordo County · forecast zone Cerro Gordo An intensifying low pressure system moved southeast across southern Minnesota into the lower Great Lakes. As the storm passed Iowa, strong subsidence took place. A tropospheric fold reached below 700 mb in the wake of the storm, enhancing the wind. Strong winds were sustained above 40 MPH for several hours over much ... 50 kt wind 0 1 $241K
2003-07-04 Thunderstorm WindClear Lake, Cerro Gordo County A very unstable air mass was in place over Iowa with surface dew points in the upper 70s to low 80s following a day with highs in the 90s. Lifted indices were in the -10 to -15 C. range as the low level jet began to strengthen during the nighttime hours. A cold front to the northwest of the state began to sink ... 52 kt wind 0 1 $8K
1996-08-04 Thunderstorm WindMason City, Cerro Gordo County Marginal severe thunderstorms moved through the Mason City area. Damage was limited around the city, however there were two injuries caused by downed trees. Both occurred in a similar fashion. A tree fell on top of a car, resulting in one injury. A short time later, a tree fell on top of three cars resulting in ... 0 1 $47K

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.

The costliest records in Cerro Gordo County since 1993, damage in 2025 dollars
DateRecordCharacterKilledInjuredDamage
2008-06-07 FloodPortland, Cerro Gordo County 0 0 $2.1M
1999-07-19 Flash FloodMason City, Cerro Gordo County 0 0 $1.9M
2018-06-08 FloodClear Lake Lake, Cerro Gordo County 0 0 $705K
2008-06-08 Flash FloodMason City, Cerro Gordo County 0 0 $685K
2014-08-23 Flash FloodMason City, Cerro Gordo County 0 0 $623K
1998-06-23 Thunderstorm WindClear Lake, Cerro Gordo County 0 0 $498K
2007-08-19 Flash FloodWinnebago Hgts, Cerro Gordo County 0 0 $391K
1999-07-02 FloodCerro Gordo County · forecast zone Cerro Gordo 0 0 $354K

Before 1993 NOAA filed damage by category, not amount, so the list above starts in 1993. The highest category filed here before then (entered as $2.5M, in the dollars of the day) holds: June 22, 1984 (tornado, Cerro Gordo County).

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 Cerro Gordo 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).

Cerro Gordo County: records per decade (the 2020s to June 30, 2026)
Hazard1950s1960s1970s1980s1990s2000s2010s2020-26
Severe thunderstorm wind211171247366830
Hail143419686025
Winter storms––––16324017
Floods––––1633303
Heavy rain––––016015
High wind and dust storms––––12201310

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

What time of year?

54% of its severe thunderstorm wind events since 1956 fell in June and July. The two busiest months are in violet.

The values, month by month

Jan 56 · Feb 37 · Mar 53 · Apr 69 · May 113 · Jun 176 · Jul 121 · Aug 83 · Sep 62 · Oct 32 · Nov 15 · Dec 37 (records).

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

Federal disaster declarations for Cerro Gordo County

FEMA's register lists 15 declarations that include Cerro Gordo County: 13 major disasters, 2 emergencies and 0 fire management assistance declarations. Most were for flood (6) and severe storm (4).

Declarations including Cerro Gordo County, newest first
DeclaredNumberTypeTitle
2020-03-23DR-4483BiologicalCovid-19 Pandemic
2020-03-13EM-3480BiologicalCovid-19
2018-08-20DR-4386Severe StormSevere Storms, Tornadoes, Straight-Line Winds, and Flooding
2016-10-31DR-4289FloodSevere Storms and Flooding
2008-05-27DR-1763Severe StormSevere Storms, Tornadoes, and Flooding
2005-09-10EM-3239HurricaneHurricane Katrina Evacuation
2004-05-25DR-1518Severe StormSevere Storms, Tornadoes, and Flooding
1999-07-22DR-1282Severe StormSevere Storms and Flooding
1998-07-02DR-1230FloodSevere Storms, Tornadoes and Flooding
1993-07-09DR-996FloodSevere Storms & Flooding
1991-12-26DR-928Severe Ice StormIce Storm
1990-09-06DR-879FloodSevere Storms & Flooding
1979-07-01DR-590TornadoHigh Winds & Tornadoes
1969-08-14DR-269FloodHeavy Rains & Flooding
1965-04-22DR-193FloodFlooding

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 Cerro Gordo County had?

NOAA's Storm Events Database holds 82 flood or flash flood records for Cerro Gordo County from 1997 to 2024, on 63 days, with 0 deaths. By flood insurance claims since 1978 (OpenFEMA, as of September 8, 2026), Cerro Gordo County ranks 895th of 2,942 U.S. counties.

The National Flood Insurance Program has paid $3.5 million on 216 claims filed in Cerro Gordo County; the most in one year was 89 in 2008. Claims count insured losses only: uninsured flood damage is not in this file.

The values, year by year

1978: 4 · 1979: 15 · 1980: 10 · 1981: 3 · 1982: 2 · 1983: 1 · 1984: 13 · 1990: 8 · 1991: 1 · 1993: 2 · 1997: 1 · 1999: 24 · 2001: 1 · 2004: 26 · 2007: 1 · 2008: 89 · 2013: 1 · 2014: 1 · 2016: 2 · 2018: 11; the other years: 0.

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 Cerro Gordo County

FEMA's National Risk Index rates Cerro Gordo County Relatively Low overall, with an expected annual loss of $27.4 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.

National Risk Index ratings for Cerro Gordo County (December 2025 release), by FEMA's rating, then score
HazardRisk ratingExpected annual lossModeled frequency
DroughtRelatively High$4.0M24 modeled event-days a year
Winter WeatherRelatively High$343K20 a year (modeled)
TornadoRelatively Moderate$6.5Monce in about 2 years (modeled)
HailRelatively Moderate$697K4.6 a year (modeled)
Cold WaveRelatively Moderate$2.5M11 a year (modeled)
Strong WindRelatively Moderate$942K3.9 a year (modeled)
Riverine FloodingRelatively Low$12M2.2 a year (modeled)
Ice StormRelatively Low$57Konce in about 2 years (modeled)

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

Counties that share a border with Cerro Gordo County

  1. Cerro Gordo County 854
  2. Butler County 734
  3. Floyd County 621
  4. Franklin County 602
  5. Wright County 598
  6. Hancock County 567
  7. Winnebago County 542
  8. Worth County 513
  9. Mitchell County 484

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

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