Winds gusts up to 45 mph helped spread the fire that started about 1 p.m. and remained out of control Sunday evening.
A dispatcher with the Pottwattamie County Sheriff's Department said at least of couple of firefighters suffered injuries, but didn't have any information on their condition.
Officials said the fires -- there were at least two of them including a large one near Carson -- stretched from Treynor to Oakland to Griswold. The cities weren't in jeopardy, authorities said.
A dispatcher told the Omaha World-Herald that at least 18 area fire departments joined to try to control the blaze. It was difficult to try to battle the fire because firefighters had to haul in water because there's no fire hydrants in the area, the official told the newspaper.
Authorities said U.S. Highway 6 and a county road were closed. Another road, U.S. Highway 92, was closed but reopened a few hours later.
