Pyrotechnics

I had to take a detour on the way home last night and wondered what this sign meant. Was it some sort of military exercise?
With a bit of googling it turns out that filming is going on nearby for a new series about the aftermath of the 1988 bombing of Pan Am 103 and the Lockerbie disaster. They  are using the old abandoned shopping outlet area it seems. It is starring Colin Firth who is playing Jim Swire whose daughter one of 270 killed on the flight and in the town that night.
A terrible tragedy that puts my delay getting home into perspective.