A stationary thunderstorm dumped extraordinary rainfall over Chicago on Tuesday night, with a personal weather station west of the United Center recording 5.06 inches in 90 minutes and National Weather Service spotters later measuring nearly seven inches within three hours along a narrow corridor stretching from the Loop to Cicero. The agency issued a flash-flood warning for Chicago and east-central Cook County through 11:45 p.m. as streets, underpasses and viaducts quickly filled with water. Emergency crews conducted multiple water rescues, including incidents near the United Center, Western and Ogden avenues, and Fulton and Maple streets. Portions of interstates and city thoroughfares were closed by standing water, and a lightning strike was reported at the John Hancock Center. While downtown and several West Side neighborhoods bore the brunt of the deluge, most suburbs saw little or no rain. The National Oceanic and Atmospheric Administration said rainfall of this intensity has a statistical likelihood of occurring only once every 500 to 1,000 years in the region, underscoring the rarity of the event. Forecasters warned that additional storms could exacerbate flooding overnight, urging residents in low-lying areas to remain vigilant and avoid inundated roadways.