CBS Chicago: Heavy rains soaking the Chicago area have prompted a flash flood warning for a huge portion of the Chicago area through late Sunday night, and officials at the Metropolitan Water Reclamation District reversed the flow of the Chicago River into Lake Michigan, dumping storm runoff and sewage into the lake.

“We have reversed the flow of the Chicago Area Waterway system to Lake Michigan at the Wilmette Pumping Station and at the Chicago River Controlling Works downtown to prevent overbank flooding,” MWRD officials wrote in a series of tweets. “There are several factors we consider when determining to release floodwater to the lake, including the rate the river water level is rising at each lakefront control location, whether the rainfall intensity is continuing or decreasing, and the storm conditions on the radar. We will continue to monitor the situation. During severe weather such as we are experiencing today the safety and health of our residents is our top priority. Please exercise caution and avoid flooded areas.”

Meantime, Lower Wacker Drive was closed due to flooding of the entire lower level, and Chicago firefighters rescued several homeless people from Lower Wacker Drive, after it flooded Sunday night. Fire Department officials said at least six people were rescued as of 11:15 p.m., and crews were searching for any more people in need.

With the ground already saturated from storms a few days ago, and several inches of rain falling since Saturday, streets, streams, and rivers have been inundated with storm runoff. The Chicago Riverwalk downtown also has flooded significantly, due to the torrential rain.

Flash flood warnings that expired late Sunday night have been replaced by areal flood warnings in Cook, DuPage, Lake, Will, Kane, McHenry, LaSalle, DeKalb, Grundy, Kankakee, Livingston, Iroquois, Kendall, and Ford counties through 1 p.m. Monday.

The National Weather Service said, while the rain was finally moving out by about 10:30 p.m., flood waters will be slow to recede, and local rivers and streams likely will continue to rise through Monday morning.

It wasn’t just Sunday’s rain that was the problem. Heavy rains a few days ago left the ground saturated, so the runoff had nowhere to go but into streets, streams, and rivers.

Even hours before Sunday’s storms began clearing out, some parts of the Chicago area already have had more than 8 inches of rain over the past five days, according to radar estimates.

There have been too many reports of flooded streets to count, with some roads turning into small rivers due to all the rain.

The National Weather Service said, even after the rain stops, the Chicago River will continue to rise through Monday morning, as storm runoff drains into the waterway.

Meantime, in north suburban Lake Forest, firefighters braved rising floodwaters to rescue drivers stranded in their cars. Fire officials said several vehicles were stuck at Deerpath Road and Skokie Highway. Firefighters were able to help everyone to safety.

Part of the Eisenhower Expressway also was shut down due to flooding. Illinois Department of Transportation trucks blocked the eastbound lanes at Des Plaines Avenue, forcing all traffic to turn around.

It was the same scene in west suburban Bellwood, with Mannheim Road and Randolph Street closed due to flooding.

Near Joliet and Plainfield, at Caton Farm and County Line roads, streets looked more like small rivers due to all the rain.

In Orland Park, Will-Cook Road has been closed between 151st and 159th, 135thStreet has been closed between LaGrange Road and Southwest Highway, and 108thAvenue has been closed from 159th Street to 163rd Street.

There also have been two unconfirmed reports of possible tornado sightings, although both appeared to be very brief, and relatively weak; one on the Grundy County and Will County line near the town of Reed, and the other near the town of Millington in Kendall and LaSalle counties.

A Lakeshore Flood Advisory goes into effect Monday and 1 a.m. and lasts through Tuesday at 1 a.m. as winds develop off the lake, and large waves up to 12 feet are possible.

A few scattered showers are possible again Monday and Tuesday, it shouldn’t add any appreciable amounts to the flooding threat, and things should dry out for a while.

https://chicago.cbslocal.com/2020/05/17/chicago-weather-rain-flash-flood-tornado/