Meteorologists with Chicago’s National Weather Service generally spend their days sitting in their Romeoville office, looking ahead — analyzing data and trends to warn some 10 million area residents what conditions to expect in the future.
Since Sunday night’s devastating thunderstorms, however, roughly half or more of the 14 meteorologists who work in the office have spent their shifts in the field, working on damage-surveying teams in Naperville, Woodridge, Darien, Burr Ridge and Willow Springs. They are trying to quantify past events to answer lingering questions about the strongest, most devastating tornado to hit the Chicago area in at least six years.
Scott Lincoln, a senior service hydrologist, said those staffers are trying to “solve the puzzle” of what happened beginning about 11:10 p.m. Sunday in Naperville.
“We’re collecting all sorts of information from radar data, to pictures, to even, sometimes, we get personal accounts from people,” Lincoln said. “They tell us about what they saw, how it behaved, how long it took, and we’re collecting all of that information, putting it in one place, and then we’re kind of doing an investigation, basically. Trying to look at all the factors together and coming to a conclusion from that.”
The weather service said Tuesday afternoon the Naperville-area tornado had a track approximately 16.1 miles long and maximum width about a third of a mile. Hundreds of homes were damaged, some leveled entirely, and at least eight people had injuries significant enough to be treated at an area hospital.
In the aftermath, Lincoln said, the weather experts are striving to document, understand and explain what happened Sunday night.
“It’s one of our most important times,” he said. “It’s one of the times when you need the information, when the public wants to know, and we need to get it documented for the official record — things like the strength of the wind and what caused it. We want to be able to answer everything we can from a technical standpoint and put the information in context.”
Among their findings as of Tuesday afternoon, meteorologist Jake Petr said the office has determined:
There were at least two tornadoes in the Chicago area, and a third in northwest Indiana. The most destructive was the one that touched down in Naperville, Woodridge and Darien, and was categorized at an EF-3 on the Enhanced Fujita scale.
As it approached the 1800 block of Princeton Circle in Naperville, the larger tornado likely had sustained wind speeds of about 140 mph. The same tornado was, at times, an EF-2, with winds as strong as 111 to 135 mph, but because it surpassed that in Naperville, the tornado was categorized as an EF-3.
A second tornado touched down near Romeoville and Plainfield as an EF-0, meaning it had wind speeds of 65 to 85 mph. And late Tuesday, the weather service said another was confirmed in the South Haven, Indiana area. It, too, was an EF-0 and peaked at 75 mph.
The EF-3 was the strongest tornado in the nine-county Chicago area since an EF-3 struck near Coal City in 2015. Sunday’s storm, on June 20, came two days shy of the sixth anniversary of that tornado.
It is possible meteorologists will confirm one more tornado. The weather service was “still investigating” damage reports from the Addison area in Illinois.
The EF-3 was the strongest and geographically closest tornado to Chicago city limits since 1991. A Fujita 3 struck that year (the weather service did not begin to use the Enhanced Fujita scale until 2007), carving a path from Romeoville to Lemont. A weaker tornado hit Rogers Park in August 2020.
The EF-3 was the strongest tornado in northern Illinois since a Naplate to Ottawa EF-3 in 2017. The most recent tornado that was stronger was a Fujita 4 in DuPage County in 1976.
The weather service also is investigating damage thought to have been caused by “straight line winds” from Kaneville to North Aurora and from far north Downers Grove to Hinsdale. Petr said straight line winds can be as damaging as a tornado, but it was too soon to say whether that was the case during this storm and it depends on a variety of factors. Straight line winds, Petr said, are similar to a tornado but do not create funnels or rotation.
Officials in Woodridge and Naperville provided updates on cleanup efforts Tuesday.
Woodridge Mayor Gina Cunningham said at a news conference her town had more than 100 homes that were significantly impacted by the tornado and hundreds more with lesser damage.
She advised residents who need to rebuild to work with knowledgeable “expert building constructors” who understand local ordinances and the permitting process. The best way to determine if a permit is needed is to call Village Hall at 630-719-4715, she said.
She said the village is continuing to work on garbage and debris pickup, and additional information will be on its website, www.woodridgeil.gov, and follow the link to a newly created tornado response page.
Village building inspectors were gathering damage estimates to be used in a possible request for a state disaster declaration.
“The recovery is going to be a long road,” said state Sen. John Curran, 41st District, who lived in Woodridge for 16 years, “but the way neighbors and friends are banding together, helping each other out throughout these communities in Woodridge and beyond, is remarkable.”
In Naperville, city crews also continued to work at clearing downed trees from roads and city property, according to an email from Kate Schultz, a spokeswoman for the city.
Additional brush collection is scheduled for June 28 to July 3 and generally will include homes south of 75th Street between Plainfield-Naperville Road and Yackley Avenue, with a few neighborhoods as far south as Royce Road included, she said.
There is an interactive map — in which residents enter their address to see if the special collection applies to them — at www.naperville.il.us on the tornado update page.
A special garbage pickup also will be held “in the hardest-hit area in the near future,” Schultz said.
She also said the 770 customers who lost power had it restored no later than 6 p.m. Monday, but because crews will be making long-term infrastructure improvements, “ongoing work may require intermittent outages” in the future. Some parts of town remain impassable, she said.
The weather service said it expected to release more information about its findings either later Tuesday or Wednesday.
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