Chicago Area Inundated by Record Floods

The worst flooding in Chicago-area history turned suburban streets into rivers, swamped hundreds of homes, and forced perilous boat and helicopter rescues Thursday, authorities said.

City crews opened the floodgates on the Chicago River into Lake Michigan for the first time in six years, sending diluted sewage into the lake and closing beaches.

Roughly 2 billion gallons of water that fell as rain across the city overwhelmed the sewer system and quickly filled the 1-billion-gallon-capacity Deep Tunnel, a massive project designed to prevent discharges into the lake.

In Chicago’s southern suburbs, thousands of homes were inundated, and many residents had to be rescued by boat. In Shorewood, five people clung to tree branches until a copter could pick them up one by one. An 84-year-old man was found dead, the victim of an apparent heart attack.

The National Weather Service reported rainfall of 17 inches in Aurora, Ill., the second-highest amount ever during a 24-hour period in the United States.