Tornadoes · United States · Iowa

Tornadoes in Lee County, Iowa

43 tornadoes have crossed Lee County since 1950, 4 of them surveyed so far this year and still preliminary, 31st of the 99 counties in Iowa with a tornado on record, an average of one every 1.8 years. They have killed 1 person and injured 12. None was rated F4 or above. Before 1950, Grazulis's record of significant tornadoes has 4 more crossing the county, back to 1838.

The rating scale

Tracks are drawn in the color of the rating. The United States rated tornadoes on Ted Fujita’s F scale until 31 January 2007 and on the Enhanced Fujita scale after it. Both run from 0 to 5, and both rate the damage rather than measure the wind: the speeds are what that damage is taken to imply.

  1. F0 / EF040 to 72 mph on the F scale, 65 to 85 mph on the EF scale

    Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

  2. F1 / EF173 to 112 mph on the F scale, 86 to 110 mph on the EF scale

    Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

  3. F2 / EF2113 to 157 mph on the F scale, 111 to 135 mph on the EF scale

    Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.

  4. F3 / EF3158 to 206 mph on the F scale, 136 to 165 mph on the EF scale

    Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

  5. F4 / EF4207 to 260 mph on the F scale, 166 to 200 mph on the EF scale

    Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

  6. F5 / EF5261 to 318 mph on the F scale, over 200 mph on the EF scale

    Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.

  7. Unrated

    The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.

Now

Tornadoes
43
Deaths
1
Injuries
12
F4 and above
0
Worst on record
F3, January 24, 1967

The deadliest in Lee County

The strongest

Every year with a tornado

The 26 years of the 76 in the record with a tornado in Lee County. Each year links to every tornado in Iowa that year.

YearTornadoesDeathsInjuriesStrongest
20264EF1
20253EF0
20241EF2
20211EF0
20191EF1
201711EF2
20152EF1
20141EF0
20101EF0
20071EF0
20044F1
20031F2
20021F0
19983F0
19901F0
19822F0
19791F1
19782F1
19771F2
19731F1
19682F0
19673110F3
19601F2
19581F0
19572F0
195411F2

Every tornado that crossed Lee County

43 tornadoes, newest first. 1 of them touched down in a neighboring state and ran in, so the record files it under that state rather than Iowa. The 4 at the top are this year's, from the surveying office rather than SPC's published database, and their ratings are marked as preliminary.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
March 10, 20269:05 PM CDTEF1Lee1.550
March 10, 20269:26 PM CDTEF1Lee2.150
March 10, 20269:38 PM CDTEF1Lee1.250
June 17, 20269:05 AM CDTEF1Lee to IL1.3100
August 10, 20257:51 PM CDTUnratedLee0.110
August 10, 20257:41 PM CDTUnratedLee0.010
June 3, 20255:58 PM CDTEF0Lee0.5100
April 16, 20244:25 PM CDTEF2Lee41.7600
March 23, 20217:19 PM CDTEF0Lee0.130
May 27, 20191:36 PM CDTEF1Lee0.520
December 4, 20175:13 PM CSTEF2Clark to IA8.0501$100,000
June 20, 20157:34 PM CDTEF1Lee4.450
May 24, 20155:42 PM CDTEF1Lee0.125$10,000
May 11, 20144:24 PM CDTEF0Lee0.130
June 21, 20105:21 PM CDTEF0Lee0.125
June 22, 20077:04 PM CDTEF0Lee0.375$1,000
May 30, 20042:30 PM CDTF1Lee0.570$20,000
May 30, 20042:26 PM CDTF0Lee0.340$10,000
May 30, 20042:23 PM CDTF1Lee0.370$20,000
May 30, 20042:18 PM CDTF0Lee0.340$3,000
May 10, 20036:28 PM CDTF2Lee11.5200$1.0 million
June 26, 200210:33 AM CDTF0Lee0.110
April 7, 19985:02 PM CDTF0Lee0.130$1,000
April 7, 19985:00 PM CDTF0Lee0.130
April 7, 19984:45 PM CDTF0Lee0.130
March 12, 199010:40 PM CSTF0Lee0.220$5,000 to $50,000
May 21, 19824:18 PM CDTF0Lee0.110under $50
May 21, 19824:18 PM CDTF0Lee0.110under $50
October 22, 19794:30 AM CDTF1Lee0.560$50,000 to $500,000
July 1, 19783:30 PM CDTF1Lee5.030$5,000 to $50,000
June 7, 19784:48 PM CDTF1Lee2.030$50,000 to $500,000
May 4, 19773:30 PM CDTF2Lee2.060$50,000 to $500,000
April 21, 19736:10 PM CSTF1Lee4.1250$5,000 to $50,000
April 28, 19688:45 PM GMT-5F0Lee0.110
April 28, 19688:45 PM GMT-5F0Lee0.110
April 30, 19676:20 PM GMT-5F2Lee2.3400$50,000 to $500,000
January 24, 19674:20 PM GMT-6F2Lee3.02004$50,000 to $500,000
January 24, 19674:15 PM GMT-6F3Lee4.330016$50,000 to $500,000
March 29, 19607:00 PM GMT-6F2Lee6.6200$500 to $5,000
March 28, 195810:30 AM GMT-6F0Lee0.110under $50
June 11, 195712:33 PM GMT-5F0Lee0.110
June 10, 19577:00 PM GMT-5F0Lee0.110$5,000 to $50,000
April 30, 19544:15 PM GMT-5F2Lee85.22001$50,000 to $500,000

Lee County before 1950

Before 1950 the record is Thomas P. Grazulis’s list of significant tornadoes: those rated F2 or stronger, and weaker ones that killed somebody. 4 of them crossed Lee County, killing 5. They are not in the figures above, which are SPC's from 1950.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 21, 19495:30 PM CSTF2N West Point, IA7.2
September 25, 19303:30 PM CSTF2NNE Keokuk/Summitville/New Boston, IA2.121
March 27, 19086:30 PM CSTF2New Boston, IA70
June 15, 18381:00 PM CSTUnratedFt. Madison, IA/Pilot Grove, IL15.93

About the record before 1950

Significant tornadoes only
Grazulis listed tornadoes rated F2 or stronger, and weaker ones that killed somebody. Most tornadoes are weaker than F2, so the list holds a fraction of the tornadoes that happened.
The early years are thin
A tornado is on record only where somebody saw it and wrote it down. The count rises through the 1800s with settlement and newspapers, not with the weather.
Rated from accounts
Grazulis rated each tornado decades later from newspaper reports, Weather Bureau records and local histories, not from a damage survey.
The tracks are reconstructed
Tornado Archive drew each path through the places Grazulis names, most often as a straight line from the first to the last. A track can miss a town it hit, and a tornado with one named place is a point. The counties are today’s.
A separate record
SPC’s database, from 1950, counts every confirmed tornado of any strength. The two are kept apart on every page and never added together.

Nearby

Warnings in force in Lee CountyThe forecast for Lee CountyThe live radar over Lee CountyEvery county in Iowa

What this means

Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.

Sources

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center. Before 1950: Thomas P. Grazulis, Significant Tornadoes 1680-1991 and Significant Tornadoes 1880-1989, as digitized by Tornado Archive (Maas and others, 2024). Public domain. Counties assigned by this site from today’s NWS county lines.