A tornado slammed into a western Iowa town on Saturday evening, severely damaging blocks of homes and businesses, newspapers reported.
Monona County Sheriff's Sgt. Roger Krohn told the Sioux City Journal that about half of the town had been damaged or destroyed by a tornado that was three-quarters of a mile wide. He said there had been no reports of serious injuries or deaths.
Law enforcement officials were going door to door to check residents.
when Mapleton warning sirens sounded, the Journal reported. Crowd and cast were sent to underground locker rooms.
Senior Maddie Walsh, who was acting in her final high school drama production, told the paper that loud crashes were heard and when the all-clear sounded, they emerged to find the roof collapsed.
"It was the kind of scene you'd see on TV, from somewhere else," Walsh said. "It was weird to be living it."
Thomas Mohrhauser, an attorney who lives in the town of about 1,200 people, says the tornado damaged commercial buildings and homes, knocked down a grain elevator and tore the roof off the high school.
"I've seen roofs gone," said Lynette Flanigan, "We've seen ambulances from all over ... coming into town."
Gov. Terry Branstad approved an emergency declaration.
Mapleton is about 40 miles southeast of Sioux City, east of Interstate 29.
High winds also damaged homes in the town Early and storm chasers reported tornadoes had touched down around Algona, which is northeast of Mapleton.
Forecasters had said that the first front of spring warmth was likely to bring strong, volatile storms, including tornadoes, to the Midwest and South.
In North Carolina, lightning struck a fairgrounds, sending at least seven people to the hospital.
The lightning strike at the Burke County Fairgrounds in Morganton came as thunderstorms showered the city with baseball-size hail. Much of the area was also under a tornado watch.
Seven people were taken from the fairgrounds by ambulance to a hospital, . Their conditions were not immediately known.
Severe thunderstorms, large hail and damaging winds were likely over the weekend from Iowa in the west to the Carolinas in the east, said Jack Hales, lead forecaster at the National Storm Prediction Center in Norman, Okla.
"These storms are not going to be messing around," Hales said.
"There already have been some very strong storms, producing damaging winds and large hail, in the lower Ohio Valley," he said. "And those are just going to continue and intensify, and spread down into Kentucky and eastern Tennessee, as the day goes on."
Further north and west, forecasters were keeping an eye on Iowa, southern Minnesota and Wisconsin, where Hales said there was a possibility of "quite a few tornadoes" Saturday and Sunday.
The peak U.S. tornado season runs from March through early July.
The culprit is a front of warm air surging northward across the country's midsection.
In Chicago, where the high temperature on Friday only reached 45 degrees, forecasters were predicting a high on Sunday of 88 degrees, the biggest 48-hour jump in April temperatures in more than three decades, according to Tom Skilling, WGN-TV's chief meteorologist.
But the dramatically warmer temperatures were expected to trigger strong winds and drenching downpours through Sunday.
"It's a typical springtime situation," Hales said. "We have a lot of heat and we have a have a lot of instability, so it results in some pretty organized severe thunderstorms."