CAMROSE: Fans screamed and ran for cover as a fierce thunderstorm caused an outdoor stage to collapse at a country music festival in central Alberta. Police said one person was killed and up to 40 others injured.

Thousands of fans were camped out at the Big Valley Jamboree in Camrose, 60 miles (100 kilometers) southeast of Edmonton, when strong winds and heavy rain struck about 6 p.m. on Saturday. The concert is billed as Canada's largest country music festival.

Camrose Police Chief Darrell Kambeitz confirmed the one death and said 15 of the injured were taken to hospitals. Canadian media said four of those injured were in critical condition. Kambeitz later said up to 40 people could have been injured, with some treated at the site.

Fearing a tornado, panicked fans scrambled to find loved ones and shelter.

``We were all racing for the exit,'' said Lori Trelenberg of Sherwood Park, Alta. ``It was devastation. It was strong and powerful. The stage just sort of crumbled.''

The Nashville-based Billy Currington band was playing when the power went out and the stage collapsed. One band member was pulled from the wreckage with a badly injured arm. Kevin Costner and his band Modern West were next to perform when the storm hit.

CFCW radio personality Danny Hooper was on the stage when the storm hit.

``I can't describe the sky _ it was brown and purple and green,'' Hooper said on CFCW. ``The massive wind blew me backwards.''

Maria Brandon and her sister, who were watching the show from bleachers near the stage, were injured as they tumbled into the wreckage.

``It was the most terrifying experience of our lives,'' she said.

Kambeitz, the police chief, told The Canadian Press that reports of dozens of people being trapped at the site were not true.

``The concert at Big Valley Jamboree was delayed and the concert bowl was being cleared when a small portion of the main stage collapsed,'' he said.

Vancouver-based country music singer Jessie Ferrel said it was a terrifying experience.

``It felt like bombs were going off around us in this concrete and steel building. Huge hits of power hitting the building, and then the lights were off,'' she told CTV News. ``People were missing and trying to find each other and there was a woman who was trying to tell everyone to stop panicking and she was panicking.''

The four-day festival in central Canada started Thursday and was scheduled to wrap up Sunday. It was not clear if authorities would continue the jamboree on Sunday, Kambeitz said.

Social networking sites were quickly abuzz with reaction.

On Twitter, the Oak Ridge Boys sent this message: ``Our prayers are with the Big Valley Jamboree. We have been there six times, including last summer. We know these folks.'' LINK..