Strong thunderstorms brought more rain and a flash-flood warning to an already deluged southwestern Wisconsin, forcing residents below four dams to evacuate.
Elsewhere, cleanup and recovery were under way in parts of the Great Lakes region hit hard by last week's storms. President George W. Bush on Monday declared north-central Ohio a disaster area, clearing the way for residents of the heavily flooded region to apply for grants for temporary housing and home repairs.
Storms and flooding were blamed for at least 20 deaths across the upper Midwest.
In Wisconsin, Bush had declared five counties federal disaster areas after last week's flooding forced people out of their homes.
As the storms rolled east on Monday, Francis Adams, 75, was struck and killed by lightning as he sought shelter from the rain under a pine on a golf course in Madison, authorities said.
It was the second deadly incident involving lightning in Madison in one week. Three people boarding a city bus Wednesday were electrocuted when lightning struck a utility pole and dropped a live wire into standing water.
In Ohio, floodwaters have receded in the heavily flooded village of Ottawa and surrounding area, officials said. About 1,000 homes in the county were affected by the high waters, and disaster estimates are expected to rise as residents continue to pump out their flooded basements.
The electricity was back on for most of the more than 1 million customers who lost power from storms across the Midwest in the past week.