STAGE COLLAPSES AT CHEAP TRICK CONCERT

Several people were hospitalized when a severe thunderstorm hit a Cheap Trick concert in Canada Sunday -- sending the stage crashing to the ground ... moments after the band ended their set.

Emergency vehicles rushed to the scene at the Ottawa Bluesfest -- where one man was reportedly treated for life-threatening injuries.  Local news outlets are saying part of the stage broke off and pierced the man's stomach.