July storm sets record with 32 tornadoes in Chicago area, weather service confirms
The Chicago area was hit by a record 32 tornadoes during the July 15 derecho storm that ripped through the region.
It was the "most prolific tornado event" to hit the Chicago area in recorded history, according to the National Weather Service, breaking the record for the most number of tornadoes reported in a single event.
A separate storm the day prior produced nine tornadoes in the Chicago area. Together, both storms resulted in a total of 41 tornadoes in the area within 36 hours.
On July 15, all the indications of a severe weather event were “maxed out,” weather service meteorologist Jake Petr told the Chicago Sun-Times.
“Even a few hours before, we were already messaging the potential for several tornadoes in our area,” Petr said.
We are in the process of wrapping up our analysis and post-survey work from the historic July 15, 2024 derecho. In totality, we confirmed 32 tornadoes in our forecast area, which is the most from a single severe weather event in our records. (1/7) #ILwx #INwx pic.twitter.com/8jCU46zoTJ
— NWS Chicago (@NWSChicago) August 8, 2024
There was a combination of warm, humid air near the ground and cooler air higher up, conditions meteorologists call a “ring of fire.”
The storm system moved through Iowa, Illinois and Indiana with damaging winds of 60 to 100 mph.
At times, the storm was producing multiple, simultaneous tornadoes. At one point, five active tornadoes were occurring in the Chicago area.
“It was certainly a historic event for the Chicago area and Northern Illinois,” Petr said.
The strongest tornado in the region, an EF-2, traveled from Channahon to Matteson in the southwest suburbs.
Four tornadoes reported in the city: on the Near West Side along the Eisenhower Expressway, in West Town, in Chicago Lawn and West Englewood, and at O’Hare Airport.
The O'Hare tornado's path was almost 4 miles long, with winds up to 80 mph, according to the weather service.
Since the storm, the weather service has analyzed over 1,500 reports of damage.
The weather service notes its technology for detecting tornadoes has greatly improved in recent years, so it is possible minor tornadoes were undercounted in the past.
Still, 32 tornadoes far surpassed the previous single-day high of 22 tornadoes set during storms in 2023 and 2014.
The weather service plans to release a final report in November.