Two children are among seven dead after tornadoes swept through central Iowa.
Emergency management officials in Madison County said four people were injured and six people were killed there on Saturday when a tornado touched down in the area south-west of Des Moines near the town of Winterset, at about 4:30pm local time.
Two children under the age of five died, and four adults.
In Lucas County, south-east of Des Moines, officials confirmed one death and multiple reported injuries when a separate tornado struck less than an hour later.
The state Department of Natural Resources said the person who died was in an RV at a campground.
The National Weather Service in Des Moines said initial photos and videos from the damage around Winterset suggested the storm was at least an EF-3 tornado, with winds typically in excess of 200 kilometres per hour.
These were Iowa's worst storms in more than 10 years
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 in the east of the state.
The storms were fuelled by warm, moist air from the Gulf of Mexico.
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 people in the Des Moines area.
The storms were Iowa's worst 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 said it did not know how many tornadoes had occurred.
Meteorologist Alex Krull said it was unusual but not unheard of to have serious storms in March in the Midwest.
He said they were more common in April and May.
But Northern Illinois University meteorology professor Victor Gensini said Saturday's storms were not nearly as unusual as the mid-December tornado in Iowa last year.
"It doesn't have to say June. It doesn't have to say May. They form whenever the ingredients are present. And they were certainly present yesterday."
Scientists have said that human-caused climate change means extreme weather events are becoming more likely..
AP/ABC
