This story was originally featured on Field & Stream.
A signal mirror is a key tool to include in any survival kit. When used correctly, a mirror can reflect sunlight with life-saving accuracy (as far as 7 miles on a clear day) to alert potential rescuers of your location. In wilderness areas, your potential target will usually be a bush plane or helicopter, but a mirror can also be used to signal people or vehicles on the ground.
First, it’s ideal to have a signal mirror with a built-in sight—a small hole in the middle of the mirror that you can peep through for better accuracy. If you’re using a mirror without a sight, hold it against your face just beside your eye. If you don’t have a mirror, other reflective surfaces—such as a stainless-steel plate or, to a lesser extent, the screen of your smartphone or handheld GPS device—can be used in a pinch.
The principals of using a signal mirror are basic but practice is necessary for quick deployment. A passing bush plane doesn’t stick around for long. Here’s how it’s done.
The right way to use a signal mirror
1. Facing the sun, place the mirror next to your eye—or, if it has a sight, hold the mirror right up to your eye to peep through the hole—and then look toward the sun.
2. Stretch out your other arm in front of you and tilt your head down until you can see the reflection of the mirror on your hand.
3. Spread open two fingers to create a V and guide the reflected light between them. Keep a small portion of the reflection visible on your fingers so you know it’s there.
4. Place your target between your two spread-out fingers while angling the mirror so that the reflected light remains between them.
5. Once the directed light is fixed on your target, flash the mirror up and down three times quickly. Three represents the universal distress signal, and flashing is also more attention-grabbing than direct light.
6. In the even that both your target and the sun are not in front of you, you’ll need to angle your body as much as 90 degrees from the sun to direct the light accurately.
7. If your target is behind you while you’re facing the sun, turn around to face your target, then lay down on your back. Hold the mirror in place while still keeping your sighting hand outstretched in front of you for accuracy.