DES MOINES, Iowa (AP) -- Seven people were killed, including two children, when a tornado swept through central Iowa, damaging buildings and knocking down trees and power lines, authorities said.
Emergency management officials in Madison County said four were injured and six people were killed Saturday when the tornado touched down in the area southwest of Des Moines near the town of Winterset around 4:30 p.m. Among those killed were two children under the age of five and four adults.
In Lucas County, officials confirmed one death and multiple reported injuries.
Thunderstorms that spawned tornadoes moved through much of Iowa from the afternoon until Saturday night with storms also causing damage in the Des Moines suburb of Norwalk, areas just east of Des Moines and other areas of eastern Iowa.
Officials reported a number of homes were damaged, roads were blocked by downed lines and tree branches were shredded by the strong winds. At one point, power outages affected about 10,000 in the Des Moines area.
The storms are the worst to occur in Iowa since 2008 when one tornado destroyed nearly 300 homes and killed nine people in the northern Iowa city of Parkersburg in May, and another storm a month later killed four boys at the Little Sioux Boy Scout ranch in western Iowa.
The National Weather Service in Des Moines tweeted early Sunday that there were at least three thunderstorms producing tornadoes, but it's "unknown at this time how many tornadoes occurred."
Meteorologist Alex Krull said it's unusual but not unheard of to have serious storms like this in March in the Midwest. He said they are more common in April and May.
Scientists have said that extreme weather events and warmer temperatures are more likely to occur with human-caused climate change. However, scientifically attributing a storm system to global warming requires specific analysis and computer simulations that take time, haven't been done and sometimes show no clear connection.
Iowa Gov. Kim Reynolds issued a disaster proclamation for Madison County, which allows state resources to be used to assist with response and recovery efforts.
"Our hearts go out to all those affected by the deadly storms that tore through our state today," Reynolds said. "Our hearts ache during this time, but I know Iowans will step up and come together to help in this time of need--they already are."
Madison County Emergency Management Director Diogenes Ayala said 25 to 30 homes were badly damaged.
"This is the worst anyone has seen in a very long time," he said.
Wendy Burkett told the Des Moines Register she and two of her three daughters were in their house Saturday afternoon when her husband, Tony, called her from a nearby shed where he was working and alerted her about a tornado warning.
Burkett said she came outside and joined him in front of the house, looking down their driveway toward the southwest. "And then we saw it. The tornado," she said. "There was debris flying around and it was getting louder and louder."
They hurried with their daughters to their basement as the tornado roared by within seconds. As they clung to each other, a window shattered outwards and water began spewing from the pipes, she said.
But within about a minute, the tornado passed by, and while the family was unhurt, their home was in ruins amid debris all around, even in the trees.
The National Weather Service in Des Moines tweeted Saturday that initial photos and videos from the damage around the community of Winterset suggested it was at least an EF-3 tornado, capable of causing severe damage, on the Enhanced Fujita scale. It said weather service teams would investigate the damage Sunday and further assess a potential rating.
EF-3 storms typically have winds in excess of 130 mph.