Hundreds of mourners gathered Monday at the grounds of the Indiana State Fair to honour the five people killed when a strong gust of wind caused a concert stage to collapse.

Friends and relatives of the victims sobbed and hugged each other at the fair's free stage area, not far from where the massive stage rigging came down in a violent crash Saturday night as spectators awaited a performance by country band Sugarland.

Recent stage collapses

July 17, 2011: A powerful thunderstorm toppled the main stage at the Ottawa Bluesfest just moments after a performance by Cheap Trick was cancelled over weather concerns. Cheap Trick escaped unharmed, but three people were severely injured and treated in hospital.

Aug. 1, 2009: The stage at Alberta's Big Valley Jamboree buckled after a fast-moving storm hit the annual country music festival, killing Donna Moore, 35, of Lloydminster, Alta., and injuring several workers. Three companies were charged last month under the province's Occupational Health and Safety Act with failing to ensure the stage was designed properly and failing to ensure the safety of workers.

During the memorial service, Indiana Governor Mitch Daniels became emotional as he praised the people who rushed to the stage to help the injured.

"There was a hero every 10 feet on Saturday night," he said.

"I cannot tell you how proud I am," Daniels said, his voice cracking, "to be the employee of six and half million people like that."

More than 40 people were injured in the collapse, while two people, including a child, remain in critical condition, reporter Wendy Woolfolk told CBC News Network on Monday from Indianapolis.

While a storm was expected, no rain was falling at the time of the collapse. Weather officials have estimated the gust that brought the rigging down at 90 to 100 km/h.

Four of the victims died at the scene: Alina Bigjohny, 23, of Fort Wayne; Christina Santiago, 29, of Chicago; Tammy Vandam, 42, of Wanatah; and 49-year-old Glenn Goodrich of Indianapolis.

Nathan Byrd, a 51-year-old stagehand from Indianapolis who was atop the rigging when it fell, died overnight.

The fair reopened Monday after being closed all of Sunday while authorities investigated the collapse site and inspected whether the structure was assembled according to requirements.

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Nikki LeRose, left, and Kelsea Jackson remember their friend Alina Bigjohny at a memorial gathering in Fort Wayne, Ind., on Sunday. Bigjohny was one of five people when a stage collapsed at the Indiana State Fair. ((The Journal Gazette/Samuel Hoffman/Associated Press))

Indiana State Police spokesman Dave Bursten said the lack of damage to structures on the fair's midway or elsewhere supported the weather service's belief that an isolated, significant wind gust caused the rigging to topple.

"All of us know without exception in Indiana the weather can change from one report to another report, and that was the case here," he said.

With files from The Associated Press