Chicago weather experts explain unprecedented July 15 tornado outbreak

CHICAGO - In the blockbuster film "The Perfect Storm," we see just how destructive Mother Nature can be when the right elements come together.

On July 15, the Chicago area saw a perfect storm of its own, but this time on land, with a record-setting number of tornadoes touching down in a single day.

In a Fox 32 special report, Chief Meteorologist Emily Wahls breaks down exactly what Mother Nature was up to that day.

"July 15 was a very busy day in the Chicago area - really across the whole Midwest," said National Weather Service Senior Meteorologist Brett Borchardt.

Borchardt is one of several meteorologists on hand that day who issued multiple tornado warnings for the entire Chicago metropolitan area and beyond.

"We saw a derecho which is a long-lived line of damaging windstorms move across the region," he said.

Borchardt said the derecho had been building for the last few days as part of a weather pattern called a "ring of fire."

"It’s really when storms parade around a dome of heat. It’s a typical pattern in the summertime. So, we had several rounds of storms move across our general area in a short span of time. I think it was five thunderstorm clusters in 48 hours," Borchardt said.

"We knew that the 15th was going to be sort of the pinnacle - the biggest thunderstorm in the whole pattern. The heat was going to be building and pooling ahead of a big cold front rushing through the region," he added.

Borchardt said they knew this storm system would bring lots of severe weather. And it did, with Mother Nature starting to turn up the heat around 3 p.m.

"We were in a level four out of five threat level for severe weather for our area. That’s pretty rare for our area. We typically see that once a year, if that," according to Borchardt.

Borchart said the Chicago National Weather Service went into all-hands-on-deck mode with every available staff member working.

"The service issued a tornado watch that included the Chicago metropolitan area. Cities do not stop tornadoes. Many metropolitan areas, such as Nashville recently, Houston, they’ve been hit by tornadoes. Chicago is not special. The lake doesn’t protect the city," he said.

Ten minutes later, the first severe thunderstorm warning is sent out, highlighting Lee, Ogle, and Winnebago counties.

Fifteen minutes after that was issued came the first tornado warning. It was for Ogle County.

At 7:38 p.m., 20 minutes later, the National Weather Service sent out the first severe thunderstorm warning covering parts of the Chicago area - Lake County in particular.

By 8 p.m., Mother Nature kicked the storm system into high gear and kept it there for the next three hours.

"In this particular day, we had four people watching radar. That’s a lot. Normally, we have two to three on an average severe weather event. We had people specifically dedicated to damaging winds, people dedicated to flash flooding and people dedicated to issuing just tornado warnings. We had three individual meteorologists issuing tornado warnings, which is very unusual, but we were ready," Borchardt said.

The Chicago National Weather Service was ready and waiting to see what the storm system would do next.

"At one point in time, there were five tornadoes sweeping across the Chicago metro at the same exact time. In recent memory, I can’t think of anything like that," he said.

That was at 9:43 p.m. The National Weather Service was tracking tornadoes in Manteno, Crestwood to Blue Island, Peotone, Oak Forest and Flossmoor to Thornton.

Before the night was over, even Borchardt and his team had to stop what they were doing and take cover in their storm shelter as a tornado also threatened their office.

"We have plans in place where we can call one of our back-up offices. In this case, it was in Gaylord, Michigan, to take over within a matter of seconds, and they were able to issue warnings for us as we took cover. When the threat was clear, we came back out and let them know we were okay. We took back over, and the operation was seamless," he said.

When the wind and the rain finally settled from this record-breaking derecho, the National Weather Service confirmed 56 tornadoes across Iowa, Wisconsin, Illinois and Indiana - with 48 of them happening in Illinois alone.

Of those four dozen tornadoes, 32 touched down in the Chicago area, 11 in Cook County and four in the city limits of Chicago - all in a single day.

"That’s the most we’ve ever had on record since 1950. That by itself is very noteworthy. Very rare for our area," according to Borchardt.

When it comes to the yearly number of tornadoes, Illinois is on track to break that record too, again, thanks to this storm system.

"So the unofficial count right now is 126 tornadoes across the state of Illinois, which if made official would make a record," according to Illinois climatologist Trent Ford.

Ford said the current record is 123 tornadoes in 2006.

The cleanup from this storm may also come with a record-breaking price tag. According to the Illinois Emergency Management Agency (IEMA), a preliminary sampling of just 2,200 homes estimates the damage at $16 million.

"Those are rough estimates," said IEMA Recovery Branch Chief Greg Nimmo. "We know there are going to be many more applicants than those 2,200 throughout the state. That number will rise significantly."

But there are some things you just can’t put a price tag on.

"The thing is it was just a very productive storm that produced a lot of severe weather. And when you think about it, there was a lot of damage, but there were no fatalities across the state and two injuries, both of which were not severe," Ford said.

Ford chalks that up to early warnings being issued as well as emergency management and forecasters being prepared and working together.

If you are wondering when, or if, we will see another derecho like this one, here are the odds.

"Derechos are pretty common in this region. We typically see one every year, but we don’t see one of that magnitude every year. That typically occurs once every five to 10 years. The last time we had a derecho of that magnitude was in August 2020," Borchardt said.

On Aug. 30, the state issued a disaster proclamation for seven counties following this storm system and is waiting to hear if its request for federal disaster assistance will be approved.

In the meantime, if you have storm damage, IEMA said you should report it to your city administrator and your county emergency management department.

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