Snow Across the Great Lakes, Central Appalachians, and Northeast; Unsettled Weather in the West

Light to moderate snow will continue into Saturday over the Great Lakes, Central Appalachians, and Northeast. This weekend into next week, a series of atmospheric rivers will bring gusty winds, periods of heavy rain, and mountain snow to northern California and the Pacific Northwest. Colder temperatures are in store for the weekend from the Great Lakes to East Coast. Read More >

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
Spatial
Temporal
County Maps
Hail
Wind
More Info

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%

Spatial Data

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

Temporal Data

Same Data as Above but for 1995-Present

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

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

For listings of the total number of tornadoes in Illinois by county from 1950-2019, see here. For the same but normalized by county area, see here. These numbers are courtesy of NWS Central Illinois.

These maps are courtesy of the NOAA Midwestern Regional Climate Center (MRCC). An interactive tornado map from the MRCC is available here. Please 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