There were at least 22 tornadoes reported in several states across the Midwest since Tuesday night, with more than half of those occurring in Illinois. The National Weather Service is at the scenes investigating the damages.
Some of the most widespread damage was found in Ottawa, Illinois, just southwest of Chicago. A 76-year-old man identified as Wayne Tuntland died outside his home in Ottawa from crushing injuries related to a fallen tree, according to the LaSalle County Coroner's Office.
OSF St. Elizabeth Medical Center in Ottawa told ABC News that as of late Tuesday night it had received 14 patients who sustained injuries as a result of the storm. Most of the injuries were bone fractures or injuries to the head caused by falling tree limbs or traffic accidents, the hospital said.
At its peak, the Ameren Utility website showed about 7,500 people without power in the Ottawa area, and just over 10,000 without power statewide Tuesday night.
Some 250 structures were damaged in the village of Naplate, Illinois, and 50 of them were heavily damaged, according to the village's office of emergency management.
As of 7 a.m. ET on Wednesday, about 2,000 customers were without power in LaSalle County, which encompasses Ottawa and Naplate, according the LaSalle County Emergency Management Agency.
There was one weather-related fatality in Crossville, Illinois, on Tuesday night, according to the White County Sheriff's Department.
Illinois Gov. Bruce Rauner announced on Tuesday night that the State Emergency Operations Center in Springfield has been activated.
The Missouri State Highway Patrol told ABC News that an apparent tornado picked up at least 15 cars from a junkyard near Interstate 55 and dumped them on the highway. One of the junk cars hit an occupied vehicle on the highway, killing its occupant, who authorities said was a resident of nearby Perryville, Missouri.
By Wednesday afternoon, tornado watches extended from Pennsylvania to Mississippi as a string of storms moved through the area and into the Northeast. The first storm hit New York City around 9 a.m. ET.
Flash flooding will also be a concern across the Ohio Valley, where flash flood watches are in effect. From Arkansas to Indiana, there were more than 70 reports of hail, some up to the size of baseballs.
The severe weather is followed by a cold front that will be making its way into the Northeast, Southeast and the Midwest this week. The cooler air could bring snowfall to some cities, according to ABC News meteorologists.
ABC News’ Matt Foster, Max Golembo, Rachel Katz, Alex Perez and Darren Reynolds contributed to this report.