More severe weather moves through Midwest as Iowa residents clean up tornado damage

The storm also brought rain that was heavy in some areas of Iowa, where totals have reached as much as 8 inches (20 centimeters) over the last week, according to the weather service.

Also Friday, a church caught fire in Madison, Wisconsin, as a thunderstorm rolled through the area. Nate Moll, who lives two doors down from Holy Redeemer Catholic Church, said he heard a "zap zap zap" electrical sound, followed by a loud crack of thunder. Firefighters extinguished the blaze.

In Oklahoma, a tornado was on the ground for about an hour Thursday evening in Jackson County and neighboring counties as a slow-moving storm moved through, according to Ryan Bunker, a meteorologist with the weather service's Norman, Oklahoma, office. News outlets reported downed power lines and outages and damage to some structures.

Severe weather was expected in areas around the U.S. throughout the long Memorial Day weekend, with a strong risk of tornadoes on Saturday in the Great Plains, particularly Kansas and Oklahoma. In New Mexico, strong winds and low humidity could fuel wildfires.

"It's really important if you have outdoor plans to make sure that you remain aware of approaching thunderstorms," said Matt Elliott, warning coordination meteorologist with the weather service's Storm Prediction Center.

"May is the peak time of year for tornadoes and for severe weather across the United States," Elliot said.

The latest severe weather comes as residents of Greenfield, Iowa, a community of about 2,000 people, have been cleaning up after a strong tornado on Tuesday. Friday's storm system inflicted heavy rains, dime-sized hail and wind gusts of 75 mph (121 kph) on a community still recovering after four people were killed and 35 others injured when a tornado destroyed more than 100 homes and hit a nearby wind farm.

Among those killed were Dean and Pam Wiggins, said their grandson Tom Wiggins.

On Thursday, he tried to find any of his grandparents' mementos that remained after the tornado demolished their home, leaving little more than its foundation. He described them as "incredibly loved by not only our family but the entire town."

Not far away, Bill Yount was cleaning up.

"It's like somebody took a bomb," said Yount, gesturing to the land — covered with wood, debris, trees stripped of their leaves, heavy machinery and equipment to clean up the mess.

He waited out the storm in a closet.

The National Weather Service determined that three separate powerful tornadoes carved paths totaling 130 miles (209 kilometers) across Iowa on Tuesday.

In addition to tornadoes, Saturday's storms could bring extremely large hail, according to Elliott with the Storm Prediction Center. The risk of strong tornadoes, large hail and damaging winds shifts into parts of Missouri, Illinois, Indiana and Kentucky on Sunday. On Monday, the Mid-Atlantic region could see some severe thunderstorms.

Tornado risks increase in May because cold, dry air that occasionally flows down from Canada clashes with moist, warm air from the Gulf of Mexico and strong upper-level winds in the atmosphere, Elliot said.