A mile-wide tornado was reported to have struck north and east of Sioux City, Iowa, about 6:30 p.m local time (7:30 p.m. ET), the National Weather Service said in a series of tweets.
At 6:37 p.m., the tornado was reported to be 10 miles west of Hinton, which is northeast of Sioux City, the weather service said.
At 7 p.m., the tornado was reported to be 5 miles east of Moville, which is just east of Sioux City.
The weather service warned people in the communities of Pierson and Correctionville to take cover.