Tornadoes in Chicago: 176 Since 1954, Ranked

Before Plainfield, the benchmark was April 21, 1967. In the late afternoon an F4 tornado tore across the southwest suburbs, ripping through Oak Lawn and the Southwest Side of Chicago along a densely populated corridor. It killed 33 people and injured around 500 — still the deadliest tornado in the Chicago metro record, and it did its worst damage in rush-hour traffic, catching drivers on open roads and at a busy intersection.

It was not alone. That same outbreak spun up several tornadoes across northern Illinois that afternoon, including a second violent F4 in the far northwest of the metro. Farther out, beyond the metro box, the outbreak also produced the notorious Belvidere tornado, which killed 24 people in Boone County — many of them students as it struck Belvidere High School at dismissal. April 21, 1967 remains one of the worst single tornado days in Illinois history, and it is the event that put the Chicago area’s tornado risk on the map decades before Plainfield.

On the afternoon of August 28, 1990, a tornado dropped out of a fast-moving supercell over Will County, southwest of Chicago, and carved through Plainfield, Crest Hill and Joliet. It killed 29 people, injured about 350, and was rated F5 — winds estimated above 261 mph. What makes it unique is the calendar. Searching every F5 in our SPC data by month, August produces exactly one: this storm. Violent tornadoes overwhelmingly strike in April, May and early June; an F5 in late summer is essentially unheard of.

Plainfield was also nearly invisible until it hit. No tornado warning was issued before it touched down — the storm was moving fast, rain-wrapped, and gave little classic radar signature. It remains one of the most-studied “no warning” events in modern forecasting, and a reason the National Weather Service overhauled how it treats fast summer supercells. You can pull the actual conditions for that day, or any date since 1970, on our historical weather lookup.

There is a persistent belief that Lake Michigan, the urban heat island, or the wall of skyscrapers somehow breaks up tornadoes before they reach the Loop. It is a myth. Tornadoes are miles-deep circulations; a few hundred feet of buildings does nothing to them. The reason downtown Chicago has never taken a direct violent hit is simple probability — the Loop is a tiny target, and most metro tornadoes form to the south and west where the warm-sector air is.

But “never a violent hit” is not “never.” The SPC record includes tornadoes touching down inside Chicago city limits, among them a March 4, 1961 tornado on the North Side that injured 115 people. NWS Chicago’s own study of significant area tornadoes reaches the same conclusion: the city is not exempt, it has simply been lucky with geometry. Every one of the 176 metro tornadoes is plotted on our interactive tornado archive map — filter to Illinois and zoom into Cook County to see how close they get.

Zoom out to all of Illinois and the numbers make the stakes plain. The SPC database lists 2,973 tornadoes statewide since 1950, with 232 deaths and just two F5s (Plainfield 1990 and a rare December 1957 tornado in southern Illinois). The Chicago metro box is only about 6% of the state’s tornadoes — but it accounts for roughly 31% of all Illinois tornado deaths. That gap is the whole story of urban tornado risk: the storms are not more frequent here, they are simply hitting far more people when they do. A weak tornado over an empty cornfield downstate and an F3 over the suburbs are the same meteorological event with completely different body counts.