Rescue signals

Rule of threes: any signal repeated three times (whistle blasts, flashes, knocks, shots, horn blasts, fires) is understood internationally as a call for help. Repeat every minute or two.

Whistle

Carry a pealess whistle (plastic, resists water and cold) hanging from your pack or neck. It carries farther than your voice and hardly tires you. Signal: 3 long blasts, pause, repeat.

Signal mirror

A flash of sunlight can be seen from very far away and is one of the best daytime signals toward airplanes, helicopters, or distant hills.

1. Signal mirror with a sighting hole (center hole): look at the target through the hole; find the reflected spot of light (on your hand or face) and tilt the mirror until that spot lands on the target.
2. Improvised mirror (makeup mirror, CD, polished can lid, phone screen): extend one arm and make a V with your fingers; place the target inside the V and move the mirror until the reflection passes over your fingers and the V.
3. Sweep the horizon with flashes even if you don't see anyone, especially when you hear engines.
4. When the aircraft sees you and responds, stop flashing directly at the cockpit: it can dazzle the pilot. Flash intermittently only so they don't lose you.

Do not flash aircraft unless you are in a real emergency.

Fire and smoke

• At night: 3 fires in a triangle (or in a straight line), about 80–100 ft (25–30 m) apart, in a clearing or on top of a hill. Have all three prepared and light them as soon as you hear an aircraft if you can't keep them burning all the time.
• By day: smoke. Against a dark background (forest) aim for white smoke: add green leaves, moss, or a little water to the fire. Against a light background (sand, snow) aim for dark smoke: a piece of rubber or a tire.
• Smoke disperses in strong wind, rain, or snow; there the mirror or ground signals work better.

Ground-to-air signals

International code of visual signals for survivors (ICAO, Annex 12). Make them with rocks, branches, logs, colored clothing, tarps, trenches in the dirt, or footprints in the snow. They should be at least 8 ft (2.5 m); bigger is better. Make them contrast with the background and have straight lines and sharp angles: nature has almost no geometric shapes, which is why they stand out from the air.

SOS in Morse: three short, three long, three short (··· ––– ···), no pauses between the letters; pause and repeat. Use it with a flashlight, car lights, a whistle, or taps on pipes or walls (useful if you're trapped in rubble: see chapter 9). You can also write "SOS" or "HELP" in large letters on the ground or on the roof.

Other visual signals: wave a brightly colored garment tied to a long pole, or both arms above your head. Spread out tarps, bags, or colored clothing in a clearing. At night, swing a chemical light stick tied to a cord in a circle or flash 3 times with the flashlight.