Why is signaling with a mirror or flares effective in emergencies?

Signaling with a mirror or flares is effective in emergencies primarily because it reflects light that can be seen from a distance. The brightness of a flare or the sunlight reflecting off a mirror can catch the attention of rescuers, ships, or aircraft who might be searching for someone in distress. This visibility is crucial in emergency situations where traditional means of communication may be unavailable or ineffective. The ability to be seen from long distances significantly increases the chances of being rescued, especially in vast areas like oceans or remote locations.