Seven people were killed, including two children, when several tornadoes swept through central Iowa, destroying homes and knocking down trees and power lines in the state’s deadliest storm in more than a decade, authorities said. Emergency management officials in Madison County said four were injured and six people were killed on Saturday when one tornado touched down in the area southwest of Des Moines near the town of Winterset around 4.30pm. Among those killed were two children under the age of five and four adults. In Lucas County, about 87km southeast of Des Moines, officials confirmed one death and multiple reported injuries when a separate tornado struck less than an hour later. Iowa Governor Kim Reynolds issued a disaster proclamation for Madison County, which allows state resources to be used to assist with recovery. “Our hearts go out to all those affected by the deadly storms that tore through our state today,” Reynolds said in a statement. In December, dozens of devastating tornadoes ripped through five US states, leaving at least 79 people dead in Kentucky – with fatalities also recorded in Tennessee, Arkansas, Missouri and Illinois. Thunderstorms that spawned Saturday’s tornadoes moved through much of Iowa from the afternoon until the 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. ‘Potentially historic’: path of five-state US tornado may be longest The storms were fuelled by warm, moist air from the Gulf of Mexico. Officials reported a number of homes were damaged or destroyed, roads were blocked by downed lines and tree branches were shredded by the strong winds. The storms are the deadliest to occur in Iowa since May 2008 when one tornado destroyed nearly 300 homes and killed nine people in the northern Iowa city of Parkersburg. Northern Illinois University meteorology professor Victor Gensini said there have been plenty of examples of deadly storms in March even though they are more common in April and May. Saturday’s storms were not nearly as unusual as the mid-December tornado outbreak that Iowa saw last year, he said. “The storms that produce these tornadoes – these supercell storms – they don’t care what the calendar says,” Gensini said. “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 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. Additional reporting by Agence France-Presse