Standing water on Chicago-area expressways turned what should have been an easy Saturday morning drive into a soggy, snarled mess after heavy rains across the Midwest closed roads, stranded residents and punched a hole through an Iowa dam.

In Chicago, officials say more than 7 inches of rain fell early Saturday, inundating the sewer system and overwhelming waterways. Water covered portions of several Chicago interstates and the commuter train tracks that run along them, leading crews to divert traffic and call in bus shuttles. Portions of Interstate 290 west of downtown were closed for several hours.

Chicago Mayor Richard Daley and other officials urged residents to call for help if they need it.

"Our goal is to get the city back to normal as quickly as possible," Daley said at a news conference Saturday.

West of Chicago in suburban Westchester, crews in boats were searching for people who were stranded in their flooded homes or trapped in cars under viaducts.

In eastern Iowa, the Lake Delhi dam failed as rising floodwater from the Maquoketa River ate a 30-foot-wide hole in the earthen dam, causing water to drop 45 feet to the river below and threatening the small town of Hopkinton.

Lake Delhi was created in the 1920s by damming the Maquoketa River. The resort area now has about 700 cabins and homes.

Areas below and above the dam had been evacuated after heavy rain has pushed the river to 23.92 feet - more than 2 feet above its previous record of 21.66 feet in 2004.

Jack Klaus, a spokesman with the Delaware County emergency management office, said warning sirens sounded in Hopkinton as water began to surround homes Saturday afternoon.

"There's going to be significant losses of property there," Klaus said.

Donna Dubberke, a meteorologist with the National Weather Service in Davenport, said areas below the dam will see an initial crest in the river caused by the dam's failure followed by a secondary crest as the high water above the dam made its way downstream.

"There will be initial wave from the sudden shot of water and a secondary shot behind it from the rainfall," she said.

Heavy rains have also wreaked havoc in the Milwaukee area in the past few days, and Gov. Jim Doyle planned to tour affected areas Saturday, including the intersection where a sink hole swallowed an SUV.

County Executive Scott Walker estimated Thursday's torrential rains caused more than $10 million in damage to public property and another $18 million to private property. Doyle has already declared a state of emergency in the county.