Illinois Environment & Hazard Risk

Throughout much of central Cook County including Chicago and nearby suburbs, very heavy rainfall caused widespread flash flooding of roadways and structures. During a 12-hour period from 3 AM to 3 PM CST, storm total rainfall in Cook County ranged from 1-9 inches, with the highest amounts in central Cook County near the border of Chicago, Cicero, and Oak Park. The magnitude of this rainfall ranged from typical to extreme, with the peak rainfall estimated to have less than a 0.2% chance of occurring in a given year. Two distinct waves of heavy rainfall occurred in the Chicago area during this event, with each period of heavy rainfall corresponding to significant flooding.||The first wave of heavy rainfall impacted the Chicago area from 4:30 AM to 11 AM CST. Within a few hours numerous residential streets were flooded and I-290 (Eisenhower Expressway) was blocked in multiple locations, as well as a stretch of I-55 (Stevenson Expressway) near Pulaski Road. Multiple water rescues were reported, most of which occurred at underpasses in Chicago and the immediate western suburbs. Runoff quickly entered the deep tunnel system and mostly filled McCook Reservoir, greatly reducing storage...

Roughly 40,000 structures sustained flood damage around the city of Chicago. The greatest impacts were felt across the southwest side near and east of Midway Airport, but reports came in from all across the city. Chicago alone accounted for approximately $230 million in flood damages.

Flash flooding was widespread across a narrow corridor in central Cook County roughly along and south of Interstate 55 with the heaviest rain falling near Midway Airport. An estimated 30,000 basements were flooded in Chicago, including in Chicago Lawn, West Lawn, Elsdon, Clearing, Garfield Ridge and Gage Park. Approximately 100 structures were damaged or destroyed from the flooding. Numerous roads and viaducts were flooded and closed. A person was reported trapped in a car that was stuck in a flooded viaduct near Gage Park, who needed to be rescued. Two to three feet of flood waters were reported on 47th Street between South Halsted Street and South Morgan Street. In Washington Park, an underpass was flooded on South Street with a vehicle stuck in the flood waters.||In Bridgeview, waist high flood waters were reported on neighborhood streets from 79th Street to 83rd Street. Flood waters 6 to 18 inches deep were reported on streets from 71th Street to 84th Street just east of Harlem Avenue. There were over a dozen water rescues in Bridgeview. In Justice, multiple streets were flooded with several inches of water. At least one car was stuck in the flood waters....

A tornado touched down about 3.2 miles east-southeast of Morrisonville at 5:01 PM CST. It hit a farmstead, destroying 3 barns and severely damaging 4 other out buildings. The tornado was rated EF2 at this location with maximum wind speeds of 112 mph. The tornado continued moving northeastward, hitting several other outbuildings and snapping trees. The tree and outbuilding damage was classified as EF1 damage with wind speeds of 100-110mph. As the tornado continued to the northeast it snapped more large trees and then hit a log home, removing 25-50% of the roof material. It also snapped many other trees on this property and destroyed a couple of small outbuildings, throwing the debris northward into a field. The tornado was rated EF2 at this location with wind speeds of 115mph. The tornado continued northeastward and moved into a wooded area, snapping and uprooting hundreds of trees along its path. It then curved north-northeastward and moved into Hewittville, a small community on the southern edge of Taylorville. Here the tornado destroyed or severely damaged multiple houses. The first house the tornado hit lost most exterior walls and the entire roof, except for the roof over...

Northwest winds gusting from 35-40 mph lofted dust from newly plowed farm fields resulting in near zero visibility across portions of northern Montgomery County in Illinois. The blowing dust significantly reduced visibility across portions of I-55 from Zanesville (Exit 63) north to Glenarm (Exit 83 ��� Sangamon County in WFO ILX), causing major accidents and resultant road closures. The first accident occurred around 10:55 am. Seventy-two vehicles were involved in the crashes that occurred in Montgomery County with 8 deaths, which happened along a 6-mile stretch of I-55 (between mile markers 72 and 78). Two semi trucks also caught fire. Also, 37 people, ages 2 to 80, were transported to area hospitals with injuries ranging from minor to critical.

The tornado began on the south side of I-270 around three-quarters of a mile west of the I-270/I-255 interchange at 8:27 PM CST. Damage in this area consisted of several downed highway signs and a bent light pole. The tornado moved northeast and intensified rapidly after crossing I-255, striking an Amazon warehouse. The west-facing walls of the warehouse collapsed inward, which was followed by multiple structural failures as the tornado moved through the complex, including the collapse of additional walls and the loss of a large segment of the roof. This was the worst damage along the entire tornado track rated EF-3. Cars in the rear of the building were strewn eastward and power lines and several large high tension towers were also destroyed. There was one person injured and 6 fatalities at the Amazon facility. The tornado weakened as it moved northeast across Sand Road, where it destroyed an unanchored mobile home and an outbuilding, snapped trees, and downed power poles. Damage in this area was rated EF-1. Further northeast, the tornado crossed South University Drive where it snapped a power pole and downed additional trees. It then crossed into the Sunset Hills Country Club...