Storm spotters in Kane County reported a brief tornado near Campton Hills just before 7 p.m. and another weak tornado near Lily Lake 6:44 p.m.
Kane County authorities also reported possible tornado damage to a structure along Plank Road near Eagle Road near Burlington. There was heavy damage to homes apparent.
"There's too much to digest to be honest with you," said Greg Kmieciak, whose home was damaged. "I really haven't even got a chance... I haven't even looked at my property, to be honest with you."
Kmieciak wasn't home when the storm hit, but his wife was.
"She called me up and she says, 'I think our house has been tornado'd?'" he recalled. "And I go, 'Really.'"
Thankfully, she wasn't hurt as fierce winds took apart their roof.
"My oldest son who lives in Sycamore called her and said, 'Are you in the basement,' and she said no. He said, 'Get down to the basement now,' and so luckily she listened to him," Kmieciak said.
Among the other damage in the area was an obliterated shed and damage to structures on a farm, and a massive half-century-old tree uprooted. The owner barely made it to safety.
"He was trying to close up, you know, batten down the hatches, trying to close up his garage doors," said Jake Stamper, friend. "He kind of got caught up in the middle of it."
But he is OK.
Kmieciak's home of 25 years is now considered unsafe, but he knows it could have been much worse.
"Bottom line, my wife is safe. That's all I care about," he said. "The rest of this stuff can be fixed, can be replaced."
WATCH | Tornado touches down near Sycamore, damaging buildings
At 6:17 p.m., the National Weather Service said a confirmed tornado was located near Sycamore, moving east at 25 mph. Storm chaser video showed a tornado touching down and causing significant damage to a house and barn, ABC7 meteorologist Phil Schwarz said.
Authorities in Ogle County said a funnel cloud was sighted two miles south of Kirkland.
WATCH | Funnel clouds spotted in DeKalb, Ogle counties
In McHenry County, the storms ripped part of a roof from a townhouse and blew over a portion of a fence.
WATCH | Storms damage roof, fence in McHenry County
The storms even prompted the air traffic control tower at O'Hare International Airport to be evacuated for about 20 minutes as severe weather passed through, the FAA said. During that time, an Elgin-based facility assumed control of the airspace for the tower.
The main threat of severe weather will be between 4 p.m. and 10 p.m., ABC7 Meteorologist Cheryl Scott said.
The entire Chicago area is under a "slight" risk - a level 2 out of 5 - for severe weather Monday, according to the Storm Prediction Center.
Slow-moving thunderstorms moved through the northern suburbs Monday morning, dumping an estimated 2 to 3 inches of rain on parts of McHenry and Lake counties, Butler said.