Tornadoes in Cook County, Illinois

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.

Tornadoes

87

Deaths

41

Injuries

916

F4 and above

2

Worst on record

F4, April 21, 1967

1. F4, Cook County, IllinoisApril 21, 196733 killed, 500 injured
2. F2, Grundy, Will and Cook counties, IllinoisNovember 12, 19652 killed, 90 injured
3. F2, DuPage and Cook counties, IllinoisMarch 12, 19762 killed, 66 injured
4. F4, DuPage and Cook counties, IllinoisJune 13, 19762 killed, 23 injured
5. F2, Cook County, IllinoisMarch 4, 19611 killed, 115 injured
6. F2, Cook County, IllinoisJune 9, 19661 killed, 30 injured

1. F4, Cook County, IllinoisApril 21, 1967F4, 15.0 mi (24 km)
2. F4, DuPage and Cook counties, IllinoisJune 13, 1976F4, 3.3 mi (5 km)
3. EF3, DuPage and Cook counties, IllinoisJune 20, 2021EF3, 17.6 mi (28 km)
4. F3, Will and Cook counties, IllinoisMarch 27, 1991F3, 15.0 mi (24 km)
5. F2, Grundy, Will and Cook counties, IllinoisNovember 12, 1965F2, 35.9 mi (58 km)
6. EF2, Grundy, Will and Cook counties, IllinoisJuly 15, 2024EF2, 34.6 mi (56 km)
7. F2, DuPage and Cook counties, IllinoisMarch 12, 1976F2, 15.1 mi (24 km)
8. F2, DuPage and Cook counties, IllinoisMay 26, 1965F2, 13.8 mi (22 km)
9. F2, DuPage and Cook counties, IllinoisSeptember 26, 1959F2, 9.3 mi (15 km)
10. F2, Cook County, IllinoisMarch 4, 1961F2, 7.9 mi (13 km)

Warnings in force in Cook CountyThe forecast for Cook CountyThe live radar over Cook CountyEvery county in Illinois

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.

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.