Audible Signals: In most places, three repetitions of any loud sound is recognized as a distress signal. In the Alps, mountaineers use six repetitions, with rescuers responding in threes, both per-minute. Regardless, it’s a good idea to leave some space between each noise, not only does a regular interval highlight the deliberateness of the call, but it also allows someone hearing it to recognize the call, then locate its source.
So, a call for help would sound like NOISE — five second gap — NOISE — five second gap — NOISE. Wait a minute or however much longer feels right and repeat regularly.
Whistle: Throw one on your keychain or attach it to a zipper pull. They’re tiny, virtually weightless and pretty much indestructible. They can also be heard up to a 1/4-mile away over land or 1/2-mile over water, enabling you to signal without a line of sight to other people. Blowing on a whistle requires vastly less effort than shouting loudly, meaning you’ll be able to keep it up for longer or do it while exhausted or injured. I keep a powerful whistle on my keychain, the ability to call for help is incredibly important if you’re outdoors doing active things, even if you’re a manly man.
Gun Shots: Depending on the environment, type of gun and ammunition and weather conditions, a gun shot may be able to be heard miles away. Make sure you deliberately space out your shots in that five second interval so you don’t just sound like a hunter who’s a bad shot.
Improvise: You can bang sticks on a hollow log, slam pots together, hit your knife on something, whatever. Anything’s likely to be more effective than shouting, but you can do that too.
Visual Signals: Use these when an audible signal won’t work, either because your potential rescuer is out of hearing range for whatever sound you can make or is in a vehicle. The trouble is, you need someone to be able to see your visual signal; particularly if you’re working with limited supplies — flare gun ammo, flashlight batteries, whatever — spend it wisely.
Flashlights: At night or in low-light conditions, a powerful LED flashlight can be visible for miles. This is where you’ll want to use morse code to avoid any potential confusion. Dot, dot, dot; dash, dash, dash; dot, dot dot. Repeat.
Mirror: You’ll find little signal mirrors in off-the-shelf survival kits. They’re not great, but can work in a pinch. To use one, look through the hole in the middle while extending your other arm out towards your “target.” Hold two fingers in a V and try to catch the sun’s reflection on them. Align the target inside the V and, with the glare lighting up your fingers, you can aim your signal.
Flares: With a hand flare, fire it and wave it over your head.
Flare Gun: Much more effective. Being able to fire it up into the air allows you to clear visual obstructions and attract attention over several miles. Don’t point it at your face.
Flags: Easily improvised; any national flag flown upside down is an international call for help. If your nation has a symmetrical flag, tie a knot in it. Any flag flown with a “ball” (read: circle) does the same. Just flying a white flag from a disabled vehicle or remote campsite will achieve the same and you can always scrawl “SOS” or similar on it as well.
Fire: Three fires arranged in a regularly-spaced row is an international distress signal. During the day, you an also attract attention with smoke. Green wood and leaves produce smoke, as do manmade materials like tires. Start a fire using dry wood and add smoke producing materials to it.
Ground-to-Air Signals: The above visual signals can work, but sometimes you’ll need to communicate a more significant message with an aircraft. We’ve all seen movies where they use huge “SOS” signs made from rocks on a beach to signal aircraft, here’s how you make those say a little more.
Create these ground-to-air signals with clothing, fabric, rocks or anything else that’s clearly visible.
When communicating with your arms, simply hold them up in a “Y” if you need help,” or with one arm raised and the other lowered, forming an “N” if you don’t need help. There’s much more sophisticated hand signals out there for military types, but those two should be all you really need.
Electronic Signals: Even outside of cell coverage, you can still use electronics to call for help. Trouble is, you’ll need that gadget, that gadget will need power and you’ll need to know how to use it.
Personal Locater Beacons: Popularized by SPOT, these can call for help virtually anywhere you can see sky. But, be aware of local rescue costs; you may be slapped with fees upwards of $50,000 in a dangerous helicopter rescue in some states, for instance. Insurance is available to offset these costs.
Texts: Even if you can’t complete a phone call, a text may make it through. Worth trying!
Cell Phones: Try calling 911 first. Doing so may be carrier agnostic and even if your call does not appear to go through, it may at least register in the system. Additionally, simply powering on your phone and allowing it to communicate with any local cell towers at least once a day while out in the sticks may leave a trail of electronic breadcrumbs, enabling rescuers to locate you if they’re looking. That’s a good idea to do even if you don’t need rescue, creating that trail may be the difference between life and death if you do wind up in trouble.
Radios: Channel 9 on CB radios (like in trucks) or consult this list of international distress frequencies. Broadcast a short call for help, giving your location to the best of your ability. Repeat at regular intervals.
Just Tell People Where You’re Going And When You’ll Be Back: Calling for help is, at best, unreliable. Know what is reliable? Telling a reliable person or entity where you’re going and when you’ll be back. If you’re not back by then, they know to call in a search party. You’ll find logs at popular trail heads, you need to log this information when acquiring a wilderness permit or just leave a note on your mom’s fridge. This has the benefit of working without batteries and even if you’re unconscious or disabled. The more information you can leave, the better, including routes, waypoints and destinations.