Coal City Tornado Strongest In Chicago Metro Area In 25 Years.

CHICAGO (CBS) -- The tornado that tore through the towns of Coal City and Braidwood on Monday evening was the strongest such storm to hit the Chicago metro area in 25 years.

The National Weather Service classified the tornado as an EF-3, with winds up to 160 miles per hour.

That ranks as the strongest Chicago metro area tornado since the deadly EF-5 that devastated the town of Plainfield in 1990.

NWS preliminary surveys have confirmed a total tornadoes across Northern Illinois on Monday.

"The heaviest damage was in Coal City (Grundy County) and Braidwood (Will County) which was caused by an EF-3 tornado, and the Woodhaven Campground in Sublette (Lee County) caused by an EF-2 tornado," the weather service said in its preliminary report.

RELATED: History Of Tornadoes In Chicago Area

The atmosphere was primed for severe weather, with very warm, humid conditions, low pressure moving north of the region, and a strong jet stream aloft.

In addition to tornado and wind damage, slow moving storms brought torrential rainfall of locally up to 3 to 5 inches to portions of Lee, Grundy, Will, and Kankakee counties, resulting in widespread flash flooding.

On August 28, 1990, a total of 29 people died and 353 people were injured when an EF-5 tornado, with 200 mph winds, pulverized Plainfield. It is believed to be the only EF-5 tornado to strike in Chicago area.

On April 20, 2004, a tornado destroyed more than half of downtown Utica. The EF-3 tornado killed nine people, including eight who died in the basement of the Milestone Bar. However, Utica, in LaSalle County, is outside the six-county Chicago metro area (Lake, Cook, Will, McHenry, DuPage and Kane counties).

In April of this year, an EF-4 tornado struck in Fairdale in DeKalb County, which is also outside the Chicago metro area. That storm killed two people and injured about two dozen others.

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