Police have confirmed the tree was struck by lightning before it crashed onto four cars that were parked in the driveway of a home.
The damage happened during an 80th birthday party for Roxanne Carrozza's father.
Carrozza was walking into the party with bunches of balloons when the tree came down. At first, she did not realize what was happening.
"All of a sudden, I hear this big BOOM! And it was pouring rain, and I thought the balloons started popping. I turned and looked and the balloons were still there, and I had - there was a bouquet of rain with all of this debris hitting me," said Carrozza.
The tree and bark covered the front lawn. Although the cars were damaged, no one was injured, and the birthday party went on as scheduled.
The stormy weather rolled in quickly Sunday afternoon, catching some drivers by surprise. Areas to the south of Chicago saw the worst of the storms.
The rough weather forced the cancellation of 325 flights at O'Hare, and as of about 10 p.m. Sunday, delays at that airport were about 45 minutes. Midway was reporting delays of about 30 minutes.
At one point, winds were so strong, they flipped over and derailed multiple cars of a freight train in central Illinois. The derailment happened about 3:45 p.m. in Toluca, about two hours south of Chicago, near Peoria.
The freight train was moving west when it was hit by the winds. 21 cars were affected.
The track is the Burlington Northern Santa Fe's main line to the west coast and handles about 80 trains a day.
"There was high wind warnings of 60 mile an hour winds and obviously it took the double stackers, there's two semi trailers on top of each other, and took the middle of the train and just laid over a bunch of the cars," said Allen Morse of the Burlington Northern Santa Fe line.
Some of the cars were pushed onto an adjacent track and a few ended up in a field. There were no injuries.
The track is expected to reopen Monday morning.