A helium-powered balloon hit a power line and crashed onto a north-central Iowa cattle pasture Friday, killing two men and injuring a third, a sheriff said.

The balloon was descending when it hit the line around 9:15 a.m. The balloon and the basket separated and the basket fell 60 feet to the ground, Franklin County Sheriff Larry Richtsmeier said.

Residents who had come out of their house to wave at the balloonists saw it hit the power line, called 911 and rushed to the scene, Richtsmeier said. They found the basket on its side in the pasture, about three miles southwest of Coulter.

Marillyn Korth and her husband had heard from neighbors that the balloon was heading in their direction so were watching for it from their living room window. They said it seemed to suddenly stop.

Their son was outside working on farm equipment and saw it hit the lines and yelled for his parents to call 911.

"I was going to go out there to wave at them because that's very exciting. We don't see very many balloons," she said. "But it didn't end up being that exciting. I'm glad at least someone was there. At least we could watch and get help."

Dr. Thomas Boylan, 62, an osteopath from Fort Collins, Colo., and Bradley Brookhart, 37, of Littleton, Colo., died at the scene, authorities said. Doug Chaplin, 58, of Albuquerque, N.M., was taken by helicopter to a hospital in Mason City, about 35 miles away, where he was listed in fair condition Friday night.

Shannon White, co-owner of Mountain Breeze Ballooning in Fort Collins, Colo., told The Coloradoan newspaper that Boylan was an excellent pilot who was respected and willing to help others.

Investigators from the sheriff's office were at the scene Friday and officials from the Federal Aviation Administration had arrived to assist in the investigation.

The balloon had launched Wednesday from Greeley, Colo., some 700 miles away. Paperwork found in one of the men's pockets indicated they had spent Thursday night in the area of Omaha, Neb., Richtsmeier said.

They were flying beneath a helium balloon, rather than a more common hot air balloon powered by propane burners, Richtsmeier said.

On Friday morning, there were high scattered clouds and winds of 15 to 20 mph from the south, Richtsmeier said.

Hampton is located in north-central Iowa.