According to the operators, the drones experienced some kind of malfunction or loss of signal, which triggered a fail safe — an automated landing. So hundreds of drones landed safely… on the surface of a river!
One local newscaster called it “a spectacular malfunction” (in a report with a brief clip of the drones gently lowering themselves into the water).
The report also notes another drone company also once lost 50 drones in a river — worth tens of thousands of dollars — during a Christmas show.