(Road) flares aka. "pyros" are like fireworks that stay in place and give off bright light and heat. Their intended use is to warn others of accidents, or for a ship in distress, to help a coast guard helicopter find it. As safety devices, they're not hard to get in some countries/states.

Extracting strontium nitrate lets you .. build explosives from readily available materials? Or it would except, as the page shows, you need a pretty good chemistry set and knowledge to do this, at which point you probably don't need pyros.

I don't know if it's just a Europe thing, but pyros are illegally used a lot at soccer (EU: football) matches and other sporting events. Picture on this page: https://scottishfsa.org/pyros-burn-young-dundee-fan/