(CNN) -- The worst flooding in almost a century forced hundreds of people from their homes in the upper Midwest, while more dangerous weather caused new misery and disruptions in the region Thursday.
A view Thursday of Main Street in downtown Findlay, Ohio, where the Blanchard River has begun to retreat.
A line of severe thunderstorms that took hours to move through the Chicago area knocked out power to more than 300,000 customers and forced the cancellation of more than 500 flights out of the city's two airports, officials said.
Delays at O'Hare International Airport were averaging more than two hours Thursday night and up to two hours at Midway Airport, according to Gregg Cunningham, spokesman for the city's Department of Aviation.
Meanwhile, officials are still trying to grasp the full impact of the flooding.
"Mother Nature was not kind to us," Ohio Gov. Ted Strickland said Thursday after touring some of the devastation.
One of the areas endured nine inches of rain in about a 24-hour period, he said. Watch one town drying out as another gets drenched »
Strickland has declared an emergency in nine counties and promised to ask the federal government for assistance.
"The major problem was a decision of Mother Nature to pour large amounts of water on this region and other regions across our country in a very short period of time," Strickland said. See where the waters have risen »
Findlay, Ohio, was enduring its worst flood in nearly 100 years, but the Blanchard River there has crested and was beginning to retreat, Reuters reported.
A heat wave was making things all the more miserable Thursday.
Cincinnati public schools canceled classes Thursday and will do the same Friday as temperatures are expected to flirt with 100, CNN affiliate WLWT reported.
Several schools have announced earlier dismissal times or other schedule changes, including Ohio's Reading Schools, which closed early.
"I used to go here, and being in that building with no air conditioning was just brutal," former Reading student Lonnie Bowling told WLWT.
President Bush declared a major disaster in three Minnesota counties Thursday, making federal funding available to flood victims. See tips for surviving floods »
"We had a mudslide off the top of the hill, and it was like an avalanche of rock, trees and debris from the top of the hill all the way down," Lynn Partington of Brownsville, Minnesota, told CNN's "American Morning."
"And it just blew the sides of the house out, and the roof dropped to the ground. Looking at the house, you'd wonder if anyone could possibly survive, but they did."
Partington said insurance would not cover the loss of his house or its contents.
Another Minnesota resident fared better, but her neighbors didn't.
"I'm fortunate. My house is still here. I'm lucky," Cheryl Kirk said of her 1856 house in Minnesota City.
Sixty feet of riverfront soil on her property washed away in 2½ hours Wednesday, she told CNN. Six neighbors' homes were condemned because of flood damage and cannot be rebuilt, but her home was spared, she said.
"It's a gorgeous house, I'm close to retirement, and I plan on staying here until I'm gone from the world," Kirk said.
As of 9 p.m. ET, flood watches and warnings were in effect in Illinois, Indiana, Iowa, Missouri, Nebraska, Ohio, South Dakota and Wisconsin. Oklahoma and Texas also had flood warnings because of rain from a different storm system.
Including deaths from that storm system, 26 people have died in recent flooding in the United States, according to an Associated Press count. See images of flooding from all over »
A woman and child waiting for a bus in Madison, Wisconsin, were electrocuted when a power line fell into the wet intersection where they were standing. A passenger who got off the bus to help also was electrocuted, CNN affiliate WISC-TV reported.
The bus driver, who also tried to help but suffered an electrical shock, and a child were hospitalized, the station reported.
The victims "were still on the ground while the smoke was covering them. I guess they died instantly because of the shock," said Derrick Williams, who said he was at the scene when the incident occurred. It happened in "less than 3 or 4 seconds. It was so quick, like, boom, boom, boom, boom." E-mail to a friend
Reuters contributed to this report.