Getting noticed at night: light signal, signal fire, phone, whistle and reflectors compared

How do I make searchers or helpers notice me at night?

At night, visual signals can be seen from afar – but only where there is a line of sight. Compared are a torch or headlamp signal, a signal fire, the phone as a signalling device, the signal whistle and reflective materials. If the phone has signal, the first step is: call the emergency number (112 in the EU). All other signals complement the emergency call; they do not replace it. Range figures are deliberately not given – they depend heavily on weather, terrain and device.

Starting situation

Legend
Method	Noticeable from afar	Works in fog, forest or without line of sight	Independent of batteries	No additional fire or dazzle risk	Understood as a distress signal	Can be kept up for a long time
Light signals at night: SOS and flashing	Yes	No	No	Partly	Partly	Depends
Signal fires and smoke signals	Yes	No	Yes	No	Partly	Partly
The phone as a signalling device: light, screen, sound, emergency function	Partly	Partly	No	Yes	Depends	No
Agreeing whistle signals: three blasts for help and group codes	Partly	Yes	Yes	Yes	Partly	Yes
Being seen in the dark: reflectors, hi-vis vest, light	Depends	No	Yes	Yes	No	Yes

Legend:● Yes◐ Partly◇ Depends○ No* = note available

Light signals at night: SOS and flashing

Effort:: Low
Needs:: Torch or headlamp, spare batteries

Noticeable from afarYes
Only within line of sight.
Works in fog, forest or without line of sightNo
Severely limited in fog and rain.
Independent of batteriesNo
No additional fire or dazzle riskPartly
No fire risk, but never shine into a cockpit – crews can be dazzled.
Understood as a distress signalPartly
SOS is internationally known; observers' knowledge of Morse is not guaranteed – rhythm and repetition matter.
Can be kept up for a long timeDepends
Depends on batteries, cold and economical use.

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Signal fires and smoke signals

Effort:: High
Needs:: Safe, open, non-flammable spot; plenty of fuel; permission

Noticeable from afarYes
Especially from the air.
Works in fog, forest or without line of sightNo
Independent of batteriesYes
No additional fire or dazzle riskNo
Can start a wildfire. Never in strong wind, drought or under a fire ban.
Understood as a distress signalPartly
Three fires are widely recognised as a distress sign.
Can be kept up for a long timePartly
Needs a lot of material; prepare it and light it only when helpers are within sight or earshot.

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The phone as a signalling device: light, screen, sound, emergency function

Effort:: Immediate
Needs:: Charged smartphone

Noticeable from afarPartly
Light weaker than good lamps.
Works in fog, forest or without line of sightPartly
Loud tones or alarms carry without line of sight too – over short distances.
Independent of batteriesNo
No additional fire or dazzle riskYes
Understood as a distress signalDepends
With signal, unambiguous via the emergency function; as light or sound only if given as a distress signal.
Can be kept up for a long timeNo
The battery is needed for calls, location and callbacks.

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Agreeing whistle signals: three blasts for help and group codes

Effort:: Low
Needs:: Signal whistle (pea-less), signals agreed beforehand

Noticeable from afarPartly
Only within earshot; wind and water drown it out.
Works in fog, forest or without line of sightYes
Works in fog and darkness.
Independent of batteriesYes
No additional fire or dazzle riskYes
Understood as a distress signalPartly
Three blasts are widely understood, but not uniformly everywhere.
Can be kept up for a long timeYes
Saves your voice.

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Being seen in the dark: reflectors, hi-vis vest, light

Effort:: Very low
Needs:: Hi-vis vest, reflectors, reflective bands

Noticeable from afarDepends
Only when light falls on them, for example from headlights or search lamps.
Works in fog, forest or without line of sightNo
Independent of batteriesYes
No additional fire or dazzle riskYes
Understood as a distress signalNo
Makes you visible but is not a distress signal.
Can be kept up for a long timeYes

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