The U.S state of Iowa experiences multiple tornadoes every year. There have been at least 3,422 recorded tornadoes since 1950. At least 2,340 people have been injured, and 100 people have died due to these tornadoes. There have been multiple tornadoes before 1950, but most of them are not recorded accurately or at all, but the most violent and deadliest tornadoes before 1950 have been recorded. The deadliest tornado was the Camanche tornado, which killed 72 people in Iowa.

2024 was a record-breaking year in Iowa. Iowa saw 125 tornadoes in 2024 which beat the previous record of 120 tornadoes in 2004. In April and May alone, Iowa saw 98 tornadoes, giving the months of April 2024 and May 2024 the second and third most tornadoes in a month, just before May 2004 which saw 57 tornadoes.

The most tornado-prone parts of Iowa are in the northeastern counties. The counties of Delaware, Black Hawk, Buchanan, Linn, and Benton on average have seen at least one strong tornado each year from 1953 to 2008.

Climatology A tornado is a violent column of air that extends from a thunderstorm to the ground. Although tornadoes can happen at any time of the year, the most popular time for tornadoes to form in Iowa is early in the spring. Iowa is in the central plains, where the Rocky Mountains to the west and the Appalachian Mountains to the east meet. This unique geography creates a funneling effect, channeling warm, moist air from the Gulf of Mexico and cool, dry air from Canada. These are the most ideal conditions for tornadoes to form, with Iowa being caught inside of Tornado Alley, along with other Great Plains states, greatly increasing the chances of a tornado to form in Iowa. +Most active months for tornadoes in Iowa from 1980 to 2024DateTornadoesMay 200457April 202449May 202449June 198448June 200848April 200140June 199036August 201436May 199834June 200134June 201431June 200428 +Most tornadoes in a day in Iowa from 1980 to 2024 DateTornadoesAugust 31, 2014 35April 11, 200128June 11, 200424May 8, 1988 22June 7, 198421July 19, 201821May 22, 2004 20April 9, 201120November 11, 201519June 1, 200118March 6, 201718

Intense tornadoes

The Enhanced Fujita Scale, or EF Scale, is used to assign a tornado a rating based on estimated wind speeds and related damage. When tornado-related damage is surveyed, it is compared to a list of damage indicators and degrees of damage, which help estimate better the range of wind speeds the tornado likely produced. From that, a rating from EF0 to EF5 is assigned. From 1974 to 2007, the Fujita Scale was used to calculate the strength of a tornado. This system had calculated the strength based on the damage delt to well-built wooden homes. Tornadoes recorded before 1974 were examined and rated accordingly. Multiple flaws including a lack of damage indicators, difference in opinion from evaluators, and no calibration of damage with relation to wind speed caused researchers from Texas Tech University to re-examine and re-do the Fujita Scale. A group of wind data experts met in 2001 and came up with 28 new damage indicators which included poles, trees, and other buildings other than just wooden frame homes. After discussion, the National Weather Service officially adopted the new scale in 2007. +EF ScaleEF RatingWind Gust Speed (mph)065-85186-1102111-1353136-1654166-2005Over 200

Pre-1900 A total of 142 recorded tornadoes touched down in Iowa before 1900. At least 540 people died and 2,186 people were injured due to these tornadoes before 1900. There have been 63 intense tornadoes with a rating of F3+, the deadliest of which was on June 3, 1860, in Camanche, killing 92. This time period for tornadoes in Iowa is the deadliest period of tornadoes in Iowa, with each recorded tornado killing on average 3.48 people. The first use of a tornado warning in the United States wasn't until March 25, 1948. This caused tornadoes before the 1950s to be more dangerous, because people thought that tornadoes would be too rare to strike a region so there was no point in issuing warnings.

Camanche Tornado On June 3, 1860, an F4 tornado touched down north of Bennett, moving across eastern Iowa, killing 20 people in rural Clinton County. It then ripped through Camanche, destroying almost every building in the town and killing 41. A raft carrying 26 was hit by the tornado and flipped, killing all but 3 men. The tornado caused an estimated $250,000 - $300,000 in damages.

Grinnell Tornado

On June 17, 1882, two tornadoes formed and intersected in Grinnell forming one tornado at F5 intensity. It travelled across central Iowa, killing a total of 68 people. 10 people died near Rippey, 7 people died in Jasper County, 39 in Grinnell, and 10 in Malcolm.

Pomeroy Tornado On July 6, 1893, an F5 tornado touched down northwest of Quimby, moving toward the town of Pomeroy. With a damage path 500 yards (460 m) wide and 55 miles (89 km) long, the tornado destroyed about 80% of the homes in Pomeroy. The tornado killed 71 people and injured 200.

+Intense (F3+) tornadoes in Iowa, pre–1900F#DateDeathsInjuriesStart locationCountyPath lengthMax widthF4‡†June 3, 186092200 of BennettCedar81.2 miles (mi) (130.68 kilometers (km))1000 yards (yds) (914.4 meters (m))F4June 18, 187105 of SuperiorDickinsonUnknownUnknown F3220GliddenCarroll11.6 mi (18.67 km)UnknownF4May 22, 1873830 of HayesvilleKeokuk41.7 mi (67.1 km)800 yds (731.52 m) F3April 11, 1876330 of Eagle GroveWright27.5 mi (44.26 km)UnknownF4April 18, 187812 of AtlanticCassUnknownUnknownF4April 21, 18781729 of Charter OakCrawford69.1 mi (111.21 km)800 yds (731.52 m)F41040 of Battle CreekIda32.5 mi (52.3 km)200 yds (182.88 m) F3June 1, 187827 of AdairAdair, Guthrie12.1 mi (19.47 km)Unknown F327 of Marble RockFloydUnknown400 yds (365.76 m)F43UnknownRockwellCerro GordoUnknownUnknownF4July 2, 187920 of CarnesSioux4.6 mi (7.4 km)UnknownF3April 18, 188002Missouri/Iowa borderDavis County15 mi (24.14 km)150 yds (137.16 m)F300BloomfieldDavis County8 mi (12.87 km)200 yds (11.77 m)F4June 9, 1880720 of MacedoniaPottawattamie15.1 mi (24.3 km)500 yds (457.2 m)F4June 11, 188126 of NorwalkWarren30.1 mi (48.44 km)300 yds (274.32 m)F318 of BrittHancock10 mi (16.09 km)50 yds (45.72 m)F3June 12, 1881010 of AdairGuthrie10 mi (16.09 km)200 yds (182.88 m)F4June 28, 1881320 of QuimbyCherokee10 mi (16.09 km)400 yds (365.76 m)F3September 26, 188107 of PostvilleFayette, Clayton, Allamakee6 mi (9.66 km)200 yds (182.88 m)F3April 8, 188203 of AmesStory12 mi (19.2 km)100 yds (91.44 m)F4June 17, 188215 of OgdenBoone33 mi (53.1 km)200 yds (182.88 m)F568300CooperGreene109.4 mi (176.06 km)800 yds (731.52 m)F4June 21, 1882550 of PrimgharO'Brien21.4 mi (34.44 km)800 yds (731.52 m)F3October 30, 188226 of DavenportScott10 mi (16.09 km)600yds (548.64 m)F4April 21, 1883210 of WoodbineHarrison10.1 mi (16.25 km)150 yds (137.16 m)F3June 11, 188308 of ElkportClayton10 mi (16.09 km)100 yds (91.44 m)F3July 4, 188400 of HubbardHardin3 mi (4.83 km)70 yds (64 m)F4June 12, 1885310 of BloomfieldDavis10.1 mi (16.25 km)200 yds (182.88 m)F3013 of FairviewMonona14 mi (22.53 km)300 yds (274.32 m)F4April 14, 1886318 of GriswoldCass54.5 mi (87.71 km)400 yds (365.76 m)F305 of ThurmanFremont, Mills, Montgomery, Pottawattamie45 mi (72.42 km)100 yds (91.44 m)F3015 of BedfordTaylor, Adams20 mi (32.19 km)200 yds (182.88 m)F3July 4, 1890040 of DawsonHardin10 mi (16.09 km)200 yds (182.88 m)F3‡018 of ChesterHoward, Fillmore County, Minnesota10 mi (16.09 km)150 yds (137.16 m)F302 of VincentWebster, Humboldt, Wright5 mi (8.05 km)200 yds (182.88 m)F3June 22, 189218 of NashuaChickasaw, Bremer15 mi (24.14 km)400 yds (365.76 m)F3‡April 11, 1893316 of Stanberry, MissouriGentry County, Missouri, Worth County, Missouri, Ringgold35 mi (56.33 km)300 yds (274.32 m)F5July 6, 189371200 of QuimbyCherokee, Buena Vista,Pocahontas, Calhoun57.6 mi (92.7 km)500 yds (457.2 m)F4May 5, 189415 of Walnut CityAppanoose, Davis32.7 mi (52.6 km)200 yds (182.88 m)F3September 21, 18943Unknown of EmmetsburgPalo Alto12.6 mi (20.28 km)UnknownF42560 of WesleyKossuth, Hancock, Cerro Gordo39.6 mi (63.73 km)1000 yds (914.4 m)F4520OsageMitchell, Howard25.3 mi (40.72 km)UnknownF4‡1670 of Rock FallsCerro Gordo, Mitchell, Mower County, Minnesota, Fillmore County, Minnesota59.9 mi (96.4 km)800 yds (731.52 m)F5‡14100 of WhittemoreKossuth, Hancock, Winnebago, Faribault County, Minnesota50.6 mi (81.43 km)1500 yds (1371.6 m)F3May 3, 189511 of AshtonOsceola5 mi (8.05 km)200 yds (182.88 m)F305 of St. CharlesMadison7 mi (11.27 km)100 yds (91.44 m)F5935 of IretonSioux13.1 mi (21.08 km)1000 yds (914.4 m)F3July 26, 189501 of ReadlynBremer, Black Hawk7 mi (11.27 km)150 yds (137.16 m)F4May 24, 18962160 of Polk CityPolk, Jasper28.1 mi (45.22 km)500 yds (457.2 m)F3September 16, 189601 of MelroseMonroe5 mi (8.05 km)400 yds (365.76 m)F4April 30, 189821 of GranvilleSioux15 mi (24.14 km)300 yds (274.32 m) F32Unknown of LaurensPocahontas7.9 mi (12.71 km)Unknown F3‡115 of Newcastle, NebraskaDixon County, Nebraska, Union County, South Dakota, Plymouth, Sioux60 mi (96.56 km)200 yds (182.88 m)F4‡May 18, 189828150StanwoodCedar, Clinton, Jackson86.7 mi (139.53 km)1000 yds (914.4 m)F4July 27, 189825 of HastingsMills, Montgomery15.2 mi (24.46 km)150 yds (137.16 m)F4April 26, 1899110 of SoldierMonona, Crawford11 mi (17.7 km)400 yds (365.76 m)F4May 16, 1899414 of EdgewoodClayton, Delaware10.8 mi (17.38 km)200 yds (182.88 m)F3May 28, 189900 of BondurantPolk, Jasper15 mi (24.14 km)200 yds (182.88 m)F3May 30, 189900 of MovilleWoodbury, Plymouth12 mi (19.31 km)200 yds (182.88 m)F318 of GlenwoodMills, Pottawattamie8 mi (12.87 km)100 yds (91.44 m)F306 of BereaAdair10 mi (16.09 km)300 yds (274.32 m)F4‡June 11, 189952 of Homer, NebraskaWoodbury13.1 mi (21.08 km)200 yds (182.88 m)

1900–1949 A total of 338 tornadoes touched down in Iowa between 1900 and 1949. At least 292 people died and 1,861 people were injured. There were 75 intense F3+ tornadoes, the deadliest of which was the 1913 Easter tornado that hit Omaha, Nebraska, making its way over the border into Iowa, killing a total of 103 people and injuring 350 others.

Omaha Easter Sunday Tornado

An F4 tornado touched down in La Vista, Nebraska, a suburb of Omaha, traveling through the city of Omaha and crossing the border into Iowa. In total, 103 people died, 9 of whom were in Iowa. The tornado had a damage path of 40.3 mi (64.86 km) long and 400 yds (365.76 m) wide.

Crawford County Tornado On May 21, 1918, an F5 tornado touched down in Crawford County, moving across the county and into Greene County as well. According to witnesses, twenty or more farms were destroyed and a couple riding in a buggy north of Churdan were caught by the tornado and died. Mattresses were carried two miles away and farms and homes were wiped completely off their foundations.(July 1993). Significant Tornadoes 1680–1991: A Chronology and Analysis of Events. St. Johnsbury, Vermont: The Tornado Project of Environmental Films. .