Tornadoes · United States · Iowa

Tornadoes in Johnson County, Iowa

46 tornadoes have crossed Johnson County since 1950, 1 of them surveyed so far this year and still preliminary, 23rd of the 99 counties in Iowa with a tornado on record, an average of one every 1.7 years. They have killed 4 people and injured 92. 1 was rated F4 or EF4 and above.

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
46
Deaths
4
Injuries
92
F4 and above
1
Worst on record
EF4, March 31, 2023

The deadliest in Johnson County

  1. EF1, Wapello, Keokuk, Iowa and Johnson counties, IowaApril 27, 20142 killed
  2. F1, Muscatine and Johnson counties, IowaApril 13, 20061 killed, 1 injured
  3. F2, Johnson County, IowaMay 22, 19621 killed

The strongest

  1. EF4 Keota–Wellman tornado, IowaMarch 31, 2023EF4, 19.9 mi (32 km)
  2. F3, Washington, Johnson and Cedar counties, IowaMay 15, 1998F3, 47.0 mi (76 km)
  3. F2, Poweshiek, Iowa and Johnson counties, IowaMay 8, 1988F2, 59.0 mi (95 km)
  4. F2, Keokuk, Washington and Johnson counties, IowaMay 8, 1988F2, 36.0 mi (58 km)
  5. F2, Keokuk, Washington and Johnson counties, IowaJune 7, 1984F2, 24.0 mi (39 km)
  6. EF2, Johnson County, IowaMarch 31, 2023EF2, 16.9 mi (27 km)
  7. EF2, Johnson County, IowaMarch 31, 2023EF2, 14.7 mi (24 km)
  8. F2, Johnson and Cedar counties, IowaMarch 22, 1991F2, 14.0 mi (23 km)
  9. F2, Iowa and Johnson counties, IowaApril 21, 1973F2, 13.2 mi (21 km)
  10. EF2, Johnson and Linn counties, IowaMarch 31, 2023EF2, 9.0 mi (14 km)

Every year with a tornado

The 23 years of the 76 in the record with a tornado in Johnson County. Each year links to every tornado in Iowa that year.

YearTornadoesDeathsInjuriesStrongest
20261EF0
20244EF1
202355EF4
20201EF1
20192EF1
20171EF0
201422EF1
20081EF0
20066131F2
20013F0
1998147F3
19913F2
19901F1
19883F2
19861F1
198411F2
19831F1
19772F1
19752F1
197422F1
197316F2
19721F1
196211F2

Every tornado that crossed Johnson County

46 tornadoes, newest first. The 1 at the top is this year's, from the surveying office rather than SPC's published database, and its rating is marked as preliminary.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
April 2, 20264:36 PM CDTEF0Johnson2.250
May 24, 20247:12 AM CDTEF0Johnson0.150
May 24, 20246:55 AM CDTEF1Muscatine15.075
May 24, 20246:45 AM CDTEF1Washington22.5150
May 24, 20246:26 AM CDTEF1Washington18.3100
March 31, 20235:06 PM CDTEF2Johnson9.075
March 31, 20234:53 PM CDTEF2Johnson14.7100
March 31, 20234:46 PM CDTEF2Johnson16.9752
March 31, 20234:37 PM CDTEF0Johnson6.150
March 31, 20234:10 PM CDTEF4Keota–Wellman tornado19.97003
May 23, 202012:30 PM CDTEF1Johnson7.050
May 29, 20198:13 PM CDTEF0Johnson0.320
May 24, 20196:36 PM CDTEF1Johnson10.875
July 21, 20175:44 PM CDTEF0Johnson0.110
April 27, 20143:20 PM CDTEF1Wapello45.71,6002$25,000
April 13, 20145:56 PM CDTEF0Johnson1.325
May 25, 200811:38 PM CDTEF0Johnson0.1100$10,000
April 13, 20069:19 PM CDTF1Johnson0.525$10,000
April 13, 20068:48 PM CDTF1Muscatine4.8176$80,000
April 13, 20068:45 PM CDTF1Muscatine9.444011$120,000
April 13, 20068:38 PM CDTF1Johnson5.1700$70,000
April 13, 20068:29 PM CDTF2Johnson4.558730$12 million
April 13, 20068:16 PM CDTF1Johnson3.6350$20,000
April 11, 20015:20 PM CDTF0Johnson0.110
April 11, 20015:02 PM CDTF0Johnson0.110
April 11, 20015:00 PM CDTF0Johnson2.050$30,000
May 15, 19985:05 PM CDTF3Washington47.040047$15 million
September 12, 19914:52 PM CDTF2Johnson7.070$50,000 to $500,000
May 29, 19918:48 PM CDTF0Johnson0.220$500 to $5,000
March 22, 19917:10 PM CSTF2Johnson14.080$50,000 to $500,000
March 8, 19904:35 PM CSTF1Johnson2.530$50,000 to $500,000
May 8, 19883:00 PM CDTF0Johnson1.020$500 to $5,000
May 8, 19882:16 PM CDTF2Keokuk36.060$50,000 to $500,000
May 8, 19881:58 PM CDTF2Poweshiek59.060$500,000 to $5 million
September 22, 19866:25 PM CDTF1Johnson0.210$5,000 to $50,000
June 7, 19849:33 PM CDTF2Keokuk24.02001$500,000 to $5 million
June 29, 19831:50 PM CDTF1Johnson31.040$50,000 to $500,000
August 15, 197712:15 AM CDTF1Johnson0.560$50,000 to $500,000
August 15, 197712:10 AM CDTF1Johnson2.060$50,000 to $500,000
November 9, 19756:35 PM CSTF1Johnson0.110$5,000 to $50,000
April 23, 19754:30 PM CDTF0Johnson0.110
July 22, 19742:25 AM CDTF1Johnson1.0150$5,000 to $50,000
April 28, 19747:20 PM CDTF1Johnson2.0502$5,000 to $50,000
April 21, 19733:40 PM CSTF2Iowa13.2106
June 5, 19726:30 PM CDTF1Johnson0.1150$5,000 to $50,000
May 22, 19629:00 PM GMT-5F2Johnson4.18001$50,000 to $500,000

Nearby

Warnings in force in Johnson CountyThe forecast for Johnson CountyThe live radar over Johnson 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.