A man was taken to hospital with life-threatening injuries and LeBreton Flats was evacuated Sunday night after strong winds caused a stage to collapse at the Cisco Ottawa Bluesfest.

Reports from the scene said the MNBA stage blew over backward from a gust of wind while Cheap Trick was performing atound 7:20 p.m.

"Cheap Trick were in the middle of their set list and the stage just started to fall backward," said one concertgoer. "It fell pretty slow so hopefully everybody got out of there, but I've never seen anything like that before. It was pretty freaky."

Ottawa paramedics said a 49-year-old man who was on stage was taken to hospital with life-threatening injuries after something pierced his abdomen. He also suffered a fractured leg and pelvis.

They said two others were taken to hospital - a male from the stage with possible spinal injuries and a 46-year-old male with chest pains who was in the crowd.

Two others were treated at the scene for ankle and knee injuries and anxiety, according to paramedics.

Police said all those injured were Bluesfest volunteers, two of which were on stage when it collapsed.

Ottawa Fire Services spokesman Marc Messier said crews searched the scene twice and didn't find anyone trapped underneath.

Bluesfest officials said all remaining shows were cancelled. They said they will be unavailable for comment until Monday. 

With a report from CTV Ottawa's Katie Griffin