A string of storms prompted a second round of severe weather alerts for Labor Day weekend.
Severe storms continued to power through the northwest suburbs Sunday evening, producing winds up to 60 mph. The National Weather Service doppler radar indicated severe thunderstorms, prompting alerts in McHenry, Lake, DuPage and Cook counties just before 8 p.m.
The storms were moving southeast at 25-30 mph, the alerts said.
Earlier storms sparked tornado warnings for Grundy, LaSalle and Kendall counties Sunday.
Those warnings were allowed to expire after the storm that prompted the warning "weakened," according to an alert from the National Weather Service.
Trained tornado spotters reported no rotating coulds were present during the storms, the alert said.
But alerts continued into Monday as the National Weather Service issued hazardous weather and rip current warnings for the Chicago area.
A hazardous beach statement was released late Sunday that expires early Tuesday evening after they say dangerous swimming conditions, with high winds and waves, and strong rip and structural currents, could be seen at the city's lakefront.
Two people were critically injured Friday when a strong line of storms raked the Chicago area, bringing down trees and power lines, knocking out power to thousands, and delaying the travel of thousands of commuters heading into a busy holiday weekend.
In one incident, a woman sitting on a couch was injured when the roof collapsed on her. The building she was in, on the 1100 block of North Ashland Avenue, was under construction at the time, officials said.
She was taken to John H. Stroger Jr. Hospital of Cook County and listed in critical condition as of 7:30.
On the northwest side of the city, a man was taken to Lutheran General Hospital and listed in critical condition after he was struck by a falling tree on the 7200 block of West Howard Street, officials said.
Officials also believe lightning from the storms started simultaneous house fires in the Geneva area.
The first incident took place around 7:18 p.m. in the 900 block of Sunset Road.
The homeowner heard the lightning strike, saw flames from the kitchen window and exited the home through the front door.
Firefighters extinguished the flames and discovered the home's gas line was damaged, according to Geneva Fire Chief Steve Olson.
An investigation of the site indicated lightning either struck the home's supply line or a nearby tree, damaging the piping and igniting the escaping gas.
A second house fire was reported at 7:42 p.m. in the 1500 block of Keim Circle while firefighters were still on the scene of the previous fire.
When firefighters arrived, neighbors were attempting to control the flames shooting out of the roof of the home with a garden hose from the front yard, according to a release from the Geneva Fire Department.
Fire officials said the center attic of the home caught fire and spreading to other parts of the roof.
No injuries were reported in either fire.
Temperatures in the Chicago area on Friday were in the upper 90s, and with high humidity the heat index was more than 100 degrees. All of that hot, humid air was fuel for the line of storms that began crossing the Wisconsin/Illinois state line in mid-afternoon.
The storms topped out at about 55,000 feet and were moving to the south and east at about 25 MPH at about 5 p.m.
Wind gusts exceeded 60 MPH in some areas and there were reports of 12 to 18-inch diameter trees down in northern suburbs. Other areas saw large hail stone falling from the sky. One of NBC Chicago's neighborhood weather sites, in Harvard, Ill., collected 3.8 inches of rainfall from the event.
Thousands of lightning strikes were recorded. Residents were advised to get inside a sturdy structure or hard-roofed automobile until the severe weather passed.
Reminder: there is no safe place outside when there is lightning, and lightning strikes are possible up to 30 minutes after a storm passes.
Full ground stops were issued at both O'Hare International and Midway International while the brunt of the storm passed overhead.
On roadways throughout the area, traffic slowed to a crawl as torrential rain diminished visibility.
As of 9 p.m. Friday, Commonwealth Edison officials reported nearly 71,000 customers were without power.