White Parachute Flare Launch
A subtle one this! Sorry for bad focus, but you'll get the jist - this is a white parachute flare being launched about a mile away at night.
These flares are used to illuminate an area, if you need light to search with, or if others need light to find you.
If you carry any white para flares, it's worth a quick look at this to see what it may look like, how long it lasts and what the emergency services may be using, if you need them to come and search for you :)