National Weather Service United States Department of Commerce
Tornadoes by Strength
Tornadoes & Significant by Year
Tornadoes Fatalities by Year
   

 

This page houses climatological tornado data for the NWS Chicago County Warning Area (CWA), a 23 county area that includes a large portion of northern Illinois and northwest Indiana.  This page can serve to help with tornado risk assessment across the local area. For more on specific tornadoes of the past, please visit the NCEI Storm Events Database, the Midwestern Regional Climate Center's Tornado Tracks Page, and our Science and Past Events Page.

Thank you to student Matthew Cello of Northern Illinois University and Stephen Strader Ph.D now at Villanova University, for their assistance in compiling, interpreting, and illustrating the statistics and spatial data.

 

 

Statistics

 

NWS Chicago CWA Tornado Counts by EF (Enhanced Fujita) Scale  1950-2017

Maximum EF Damage

Count

Mean Length (mi)

Mean Width (yds)

Fatalities

Injuries

EF-0

227

1.14

43.4

0

7

EF-1

236

3.20

88.6

2

53

EF-2

113

7.13

147.9

10

469

EF-3

27

18.8

360.1

14

140

EF-4

11

28.62

681.8

90

1,660

EF-5

1

16.40

600.0

29

350

All Tornadoes

615

4.32

106.2

145

2,679

           

Significant (EF-2+)

152

10.81

227.2

143

2,619

Violent (EF-4+)

12

27.60

675.0

119

2,010

 

For more on the Enhanced Fujita Scale for tornado damage, visit here.

 

 
NWS Chicago CWA Tornado Percentage Counts by Magnitude 1950-2017
 

EF Damage

% of All Tornadoes

EF-0

36.9%

EF-1

38.4%

EF-2

18.4%

EF-3

4.4%

EF-4

1.8%

EF-5

0.2%

   

Significant (EF-2+)

24.8%

Violent (EF-4+)

2.0%

 

Tornado Count

 

Spatial Data

Tornado Map

 

Tornado Counts by County Tornado Normalized by County Tornado Fatalities

 

Tornado Paths Across the U.S. From 1950 - Present
Tornado Paths Across the U.S.  (1950-Present)

 

Annual Number of Tornadoes Annual Number of Tornadoes

 

Temporal Data

 

Tornadoes by Time of Year

One Week Running Mean 15-Day Running Mean

 

 

Tornadoes & Significant by Time of Year

 

Same Data as Above but for 1995-Present
Tornadoes by Time of Year Since 1995 Tornadoes & Significant by Time of Year

 

 

Tornadoes by Hour

Tornadoes & Significant by Time of Day Tornadoes by Time of Day Since 1995 Tornadoes by Time of Day in the Cool Season

 

For the entire state of Illinois, see these graphics:  Time of Year  |   Time of Day

For the entire U.S., see these graphics:  Time of Year   |   Time of Day

 

 

Year-To-Year Charts

 

NWS Chicago CWA Annual Tornadoes & Significant Tornadoes
Annual Tornadoes & Significant Tornadoes

 

 

NWS Chicago CWA Annual Tornado Fatalities
1950 to 2014
Fatalities by Year in the NWS Chicago CWA

 

For tornado trends across the United States, visit here, and for significant tornado trends, see here.

 

 

County Scale

 

These maps are courtesy of the NOAA Midwestern Regional Climate Center (MRCC).  An interactive tornado map from the MRCC is available herePlease note that these maps are created by the documented beginning and end points of the tornadoes.  These plotted paths do not take into account the exact tornado tracks that often have subtle deviations. Thus these plotted paths are always straight lines.  While these are really sound approximations of the historical tornado paths, they should not be considered exactly precise.

 

Illinois

 

Boone Cook DeKalb DuPage Ford
Boone County Cook County DeKalb County DuPage County Ford County

 

Grundy Iroquois Kane Kankakee Kendall
Grundy County Iroquois County Kane County Kankakee County Kendall County

 

Lake LaSalle Lee Livingston McHenry
Lake County LaSalle County Lee County Livingston County McHenry County

 

Ogle Winnebago Will
Ogle County Winnebago County Will County

 

 

Indiana

 

Benton Jasper Lake Newton Porter
Benton County Jasper County Lake County Newton County Porter County

 

 

 

 

Severe Hail Climatology in Northern Illinois & Northwest Indiana

 

Hail by Time of Year

For a 15-day running mean graph of hail of any size across the local area, see here.

 

Significant Hail by Time of Year

 

Hail by Time of Day

 

 

Severe Wind Climatology in Northern Illinois & Northwest Indiana

 

Severe Wind by Month

 

Severe Wind 15-Day Running Mean

 

Severe Wind by Time of Day