THE CANADIAN PRESS — OTTAWA - A sudden violent gale toppled the main stage at Ottawa Bluesfest in the middle of a Cheap Trick concert Sunday, sending thousands of people scurrying for cover as scaffolding buckled and tumbled onto electronic equipment.
At least four people were injured, one seriously.
Dramatic video of the moment the stage collapsed was posted here. More fan video below
Eyewitnesses said band members were tossed off their feet when the storm struck shortly before 8 p.m. EDT, but Cheap Trick posted a statement on their Facebook page to say they were shaken but unscathed.
"Everyone is okay and we are so lucky to be alive and hope that all the fans are okay too," the band, best known for hits including "Surrender", "I Want You to Want Me" and "The Flame", said in a message posted on Facebook.
VIEW FAN VIDEOS OF THE AFTERMATH BELOW
Video of the Bluesfest site posted on YouTube showed the stage — which stood several storeys tall — being propelled backward before crumpling and damaging a tractor-trailer truck parked behind it.
Without elaborating, Cheap Trick lead singer Robin Zander ended the band's Internet posting with the words, "And all the best to our truck driver Sandy."
Band manager Dave Frey told CNN "one of our drivers will spend the night in the hospital."
Twisted shards of metal jutted out from the devastated stage, which was cordoned off as concert-goers filed out of the large venue adjacent to the Canadian War Museum.
Bryce Wilson, 12, had just caught a guitar pick when he looked up and saw the stage lights swaying.
"Thirty seconds later the whole thing just fell down right in front of us. Before it fell all the way down I was already running.
"We were really scared."
His mother, Leanne, said the stage slowly heaved backwards and caved in.
"In less than 10 seconds it was gone," she said. "They were playing right until it fell. And then instantly everybody was just running and screaming.
"I was stunned, I'd never seen anything like that before at a concert."
Another fan said he was just walking away from the main stage when the storm hit.
Michael Robert, 29, said he was 15 to 20 metres away when he turned and saw the stage "start to buckle and just sort of folded in on itself and collapsed."
"The whole thing just came down in a few seconds."
Marc Messier, a spokesman for the Ottawa fire service, said a 49-year-old man was in serious condition with abdominal, pelvic and leg injuries. Another had a spinal injury and a third person experienced chest pains. There were no details on the condition of the band's driver.
At least eight other people were treated at the scene for minor issues including twisted ankles and anxiety.
Bluesfest is one of North America's largest musical events. The festival first took place in 1994 and has since grown from a one-stage, three-day event to a multi-staged, 12-day music showcase featuring some of the best international talent.
Bluesfest issued a statement saying that "due to extreme weather conditions, we have regrettably had to shut down all stages for the night." A keenly anticipated show by indie rockers Death Cab For Cutie was among those cancelled.
A deadly storm shut down a country music festival in Camrose, Alta., in July 2009. Actor Kevin Costner and his band Modern West were just going on stage at the Big Valley Jamboree when the storm hit.
The stage collapsed killing one woman and injuring 75 people.
An official with Bluesfest, who did not want to be identified, said the situation was chaotic in the moments following the stage's collapse.
But Robert said fellow fans didn't seem to panic.
"It was fairly orderly. People were aware that something serious was going on.
"There wasn't any pushing or shoving."
Said concert attendee Jordan Potechin: "When we were walking away from it all we could hear were sirens, coming from every direction, fire trucks, police."
The windstorm caused major power outages across the Ottawa region. Police said they received more than 300 emergency calls in a two-hour period.
WATCH: FIVE VIDEOS OF THE AFTERMATH
By Jim Bronskill, The Canadian Press.