It doesn't look like drone footage to me. Even DJI can't hold a position that steady, not to mention it looks like a land based video, not from the air. Cool footage though, sad loss. I'd like to see drone video of the carnage afterwards.
They already knew it was due to fall. You’ll note the drone video starts looking at exactly where the first cable snapped. These cables were already suspect and they had planned to destroy the array with controlled demolitions; this just managed to happen before they could do it in a controlled manner.