The huge breach in an embankment holding back Lake Delton released a torrent that washed away three houses and a stretch of highway. The weekend's storm also displaced thousands of Indiana residents and was blamed for 15 deaths in the Midwest and elsewhere.
Wisconsin Gov. Jim Doyle said the Federal Emergency Management Agency would have teams in the state Wednesday to help assess flood damage, and his office said he would seek a federal disaster declaration when that was done.
National Guard teams flew over flooded areas to look at other dams Tuesday, said Mike Goetzman, a spokesman for Wisconsin Emergency Management.
State crews on the ground visited dams throughout the southern and western part of the state to assess damage from the weekend storms. They also monitored water levels at dams that were seeping or consider in danger of failing, Wisconsin Emergency Management spokeswoman Jessica Iverson said.
About 30 miles southwest of Milwaukee, state and local officials were keeping watch on a dam that impounds the Mukwonago River to create the Upper and Lower Phantom Lakes.
However, no significant damage was reported at any of the dams, and water at some reservoirs had started to recede Tuesday.
At Lake Delton, a dozen workers were stretching a temporary sewer line across the 200-yard breach in the embankment where the water spilling out of the 267-acre lake had carved a new channel to the Wisconsin River. The water had ripped apart underground sewer lines and raw sewage was pouring out of the pipes and running downstream Tuesday.
Meanwhile, frantic sandbagging efforts continued in the southwest Indiana towns of Elnora and Edwards Port with the National Guard fighting to hold back the White River, reports CBS News correspondent Cynthia Bowers.
There was no time to sandbag in the south central town of Columbus, where raging floodwaters swallowed up entire neighborhoods without warning, reports Bowers.
The weekend downpours across the Midwest also created flooding concerns along the Mississippi River. The National Weather Service on Tuesday predicted crests of 10 feet above flood stage and higher over the next two weeks at places including Hannibal, Mo., and Quincy and Grafton, Ill. Most of the towns are protected by levees, but outlying areas could be flooded.
"This is major flooding," weather service hydrologist Karl Sieczynski said of the Mississippi. He urged people in unprotected flood plain areas to seek higher ground.
Levee breaks Tuesday in southeastern Illinois flooded 50 to 75 square miles of farm land along the Embarras River, forcing the evacuations of an unspecified number of homes northeast of Lawrenceville, said Lawrence County Sheriff Russell Adams. He said water was up to the roofs of some rural homes.
And in Iowa, officials in Cedar Falls told downtown residents and business owners to prepare for possible evacuations as the Cedar River threatened to top the area's protective levee.
Minnesota Gov. Tim Pawlenty signed an executive order Tuesday declaring a state of emergency in two counties hit by flooding in the state's southeast corner.
Elsewhere, the East Coast baked in a heat wave with temperatures in the upper 90s from Georgia all the way to northern New England, where the weather service reported a Tuesday afternoon high of 99 at Portsmouth, N.H.
Thunderstorms promising relief from the heat for parts of the Northeast knocked out power Tuesday to 50,000 homes and businesses in upstate New York.
About 70 miles southwest of Lake Delton, the village of Gays Mills was inundated during the weekend, just 10 months after another devastating flood left residents working to rebuild homes and businesses.
The swollen Kickapoo River engulfed nearly the entire town Monday morning, forcing about 150 of the 625 residents to evacuate. By evening, the village was a grid of canals with cars submerged up to their windows, a repeat of last August's flooding.
The weekend death toll included eight in Michigan, three in Indiana, two in Oklahoma, and one each in Iowa and Connecticut.