The company says about 150 patrons would not leave and when the storm hit it knocked over trusses and the entrance collapsed on them.
Fans injured in storm at Backstreet Boys Oklahoma concert
At least 14 people have been injured and taken to hospitals after trusses holding up the entrance to a resort where the Backstreet Boys were set to begin a concert in Oklahoma collapsed.
WinStar World Casino and Resort says in a statement posted on Twitter Saturday that the resort began an evacuation at about 5pm when lightning was within four miles of the casino.
The company says about 150 patrons did not leave and when the storm hit with 113-128kph winds, it knocked over trusses and the entrance collapsed on them. Of the 14 people taken to a hospital, two have been released.
WinStar later said the concert was postponed to a later date. Band member Kevin Richardson tweeted that the concert would be held again.