The Iowa State Patrol has confirmed multiple deaths from a tornado and at least a dozen injuries in storms on Tuesday, but it has not released specific numbers.

“We do have confirmed fatalities,” Iowa State Patrol sergeant Alex Dinkla said at a news conference on Tuesday night. He said authorities were still determining the total number.

Powerful storms that rolled through the US Midwest spun up multiple tornadoes, including a fierce tornado that smashed through the small Iowa town of Greenfield, with a population of about 2,000 around 55 miles southwest of Des Moines.

The tornado carved a bleak landscape of destroyed homes and businesses, shredded trees, smashed cars and widely strewn debris.

In the aftermath of the storm, parts of Greenfield appeared devastated.

Mounds of broken wood, branches, car parts and other debris littered lots where homes once stood.

Residents helped each other salvage furniture and other belongings from mounds of debris or from homes barely left standing.

Multiple tornadoes were reported throughout the state, and one also apparently took down several 76-metre wind turbines.

Des Moines, Iowa, television station KCCI-TV showed at least three wind turbines that were toppled by an apparent tornado in southwest Iowa, and at least one was in flames with black smoke pluming from the bent structure.

Wind farms are built to withstand tornadoes, hurricanes and other powerful winds. According to the US Department of Energy, turbines are designed to shut off when winds exceed certain thresholds, typically around 55 mph.

They also lock and feather their blades, and turn into the wind, to minimise the strain.

The Adair County Health System hospital in Greenfield was damaged in the storm, but Mercy One spokesman Todd Mizener said he had no further details.

The hospital is affiliated with Mercy One, and officials were on their way to Greenfield to assess the damage.

In far southwestern Iowa, video posted to social media showed a tornado just northwest of Red Oak. Further east and north, the National Weather Service issued multiple tornado warnings for areas near the towns of Griswold, Corning, Fontanelle and Guthrie Centre, among others.

The storms and tornado warnings moved into Wisconsin Tuesday evening and night, including a warning for the state’s capital city of Madison.