HUGO, Minn. (AP) – Severe thunderstorms packing large hail and possible tornadoes rumbled across the nation’s midsection on Sunday, killing at least one person, injuring at least eight others and damaging dozens of homes.

At least seven people were killed in northeastern Iowa, authorities said.

In Minnesota, at least 20 people were unaccounted for after a swift storm blew through the St. Paul suburb of Hugo, damaging about four dozen homes, City Administrator Mike Ericson said.

Many of them could be out of town for the holiday weekend, he said.

A 2-year-old child was killed and the child’s sibling was critically injured and taken to Regions Hospital in St. Paul, Washington County Sheriff Bill Hutton said. The children’s parents also were hospitalized with injuries sustained in the family home.

“It’s horrible,” Ericson said. “The citizens are very shook and scared.”

Residents reported a tornado touching down in the area, but that hadn’t been confirmed by the National Weather Service.

Emergency crews descended on the town to look for those who hadn’t been accounted for and to assess the damage.

Jim Waterbury, a spokesman for Allen Hospital in Waterloo, Iowa, said people came from nearby Grundy Center, Aplington and Eldora for treatment of mild to moderate injuries.

“It looks like most of them are fractures and broken collarbones,” Waterbury said. “One is in critical condition.”

Officials opened Parkersburg’s elementary school for evacuees.

A possible tornado also struck the nearby town of Dunkerton, with reports of structures damaged in both cities and in rural Black Hawk County.

Power lines have also been knocked down in the area, leaving many residents without power.

About 100 people have died in U.S. twisters so far this year, the worst toll in a decade, according to the weather service, and the danger has not passed yet. Tornado season typically peaks in the spring and early summer, then again in the late fall.