Video text translates as:
"On Sunday, about 18 O'clock, a strong gust of wind was recorded at the big event stage the Super Sail event, and it turned-over. The stage was lying on it's back, there were no casualties. The Westerländer firefighters secured the structure, and salvaged the stage in the hours that followed."
Ocean + Wind-powered Boats = HIGH LIKELIHOOD FOR WIND. This was foreseeable.