In the wild, the survival environment is far more perilous than in the city, and various emergencies may occur unexpectedly. For wilderness survivors, it's crucial to promptly understand the situation you're facing, notify others, and get rescued.
When in distress and seeking help, you must use various methods to establish contact with the outside world. The signals you send out should be...……

Auditory Signals
If you're relatively close, you can shout loudly or strike tree trunks with a wooden stick. A survival whistle is even more effective. The pattern should be three short blasts, three long blasts, then three short blasts, and repeat after a one-minute interval.

Smoke Signals
Lighting three fires in a row is an internationally recognized distress signal. Arrange the fires in a triangle with equal spacing between them for the best effect, as this also makes them easier to light. If fuel is scarce, or if you’re seriously injured, or too weak from hunger, and can't manage three fires, then lighting just one fire is acceptable.
The fuel for the fire should be easy to ignite and burn quickly, as opportunities may be fleeting. Birch bark is an ideal choice. If possible, gasoline can be used, but never pour it directly onto the fire. Instead, soak some cloth in gasoline to make a wick, place it on top of the fuel pile, move the gasoline container to a safe location, and then ignite it. When adding more gasoline to a dying fire, make sure to pour it onto fuel that has no sparks or embers—otherwise, a sudden flare-up could injure you.
During the day, smoke serves as an excellent locator. Adding green grass, leaves, moss, or ferns to the fire will produce thick smoke. When the smoke rises, it creates a strong contrast with the surrounding environment, making it easier to spot. In fact, any damp material can produce smoke—damp straw mats or cushions can smolder for a long time while also keeping insects at bay. At night, use dry wood to keep the fire strong and bright.
Additionally, black smoke is most visible in snowy or desert areas. Rubber and gasoline can produce black smoke.
If weather conditions restrict the smoke to low altitudes, intensify the fire so that rising warm air carries the smoke higher.

Flag Signals
Tie a flag or brightly colored piece of fabric to a stick. When waving it, make long strokes to the left and short strokes to the right, exaggerating your movements to create an “8” shape.
If you’re relatively close to the target, you don’t need to form an “8”. A simple stroke will suffice—one long movement to the left and one short to the right, with the former lasting slightly longer than the latter.

Ground Marking Signals
In open areas such as grasslands, beaches, or snowfields, you can create ground markings. For example, cut patterns into the grass, stomp out signs in the snow, or arrange branches and seaweed into signaling shapes to communicate with aircraft. You can also follow the internationally standardized ground-to-air symbols used in civil aviation. Remember these words: SOS (distress), SEND (send), DOCTOR (doctor), HELP (help), INJURY (injury), TRAPPED (trapped), LOST (lost), WATER (water).
Body Signals
When a search aircraft is nearby, wave clothing in bright contrast to the surroundings with large, exaggerated motions to signal distress.

Leaving Messages
When leaving a dangerous area, leave some markers (such as broken branches or arranged stones) in case rescuers find them. Ground markers can inform rescuers of your location or previous whereabouts, while directional markers help them trace your path. Keep placing markers along your route. This not only helps rescuers track you down, but also prevents you from getting lost if you need to return—if you lose your way or can't find the route you intended, they can serve as guides.

Reflective Signals
Using sunlight and a reflective surface, you can send out a bright signal. Any shiny material can be used—such as a can lid, glass, a piece of metal, or, ideally, a mirror. A continuous reflection will produce a steady line and dot, which is a form of Morse code. Even if you don't know Morse code, random reflections might still catch attention. In any case, you should at least master the SOS code.
A reflected light signal can be seen even from considerable distances, even if you don't know the exact location of the person or party you're trying to contact—so it’s worth trying repeatedly, and it takes minimal effort. Keep scanning the sky, and if you see an aircraft approaching, quickly flash the reflective signal. Be aware that this light may blind rescuers, so once you're certain you've been spotted, stop reflecting immediately.

Directional indicators include:
1. Arrange rocks or stone fragments into an arrow shape.
2. Prop a stick between tree branches, with the top pointing in the direction of travel.
3. Tie a knot in the upper-middle part of a clump of grass or reeds, bending the top to indicate the direction.
4. Place a forked branch on the ground and point the fork in the direction of travel.
5. Build a cairn of small stones, and place a single smaller stone next to it pointing in the direction you’re heading.
6. A deeply carved arrow-shaped groove in a tree trunk indicates the direction to go.
7. Two crossed sticks or stones mean that the path is blocked.
8. A signal made with three rocks, sticks, or bushes conveys a clear message of danger or emergency.