Similar to the previous question that turned up when I searched on this topic: Is there a standard set of light signals for mountaineers?, but for sound?

Repeating sets of 3 blasts is standard for distress. Freedom of the Hills mentions pre-arranging a communication system with your party (e.g., 1 blast = general "how are you" query; 2 blasts = "I'm fine"; 3 blasts = "Help!"). Any other common codes used for simple communication between separated members of a party?

The main thing that seems to be missing from the basic code outlined by Freedom is some clarification around the "I'm fine" response. "I'm fine; keep going" vs "I'm fine; wait for me". And from the group's perspective, telling the separated person to return vs continuing to forge their own path. Anyone know of or worked out a simple system for this sort of signal?

Granted, "don't get separated" is a good rule to follow, but things happen, so would be good to have a communication system in place.

  • 1
    It might be argued that this goes against Leave No Trace, as you're supposed to let the sounds of nature prevail.
    – tsturzl
    Mar 20, 2017 at 21:14
  • 7
    Leave No Trace becomes negligible if there is an acute danger for human life.
    – helm
    Mar 20, 2017 at 22:16
  • 1
    I would think that in dense woods any means of noise would not travel very far.
    – Ken Graham
    Mar 21, 2017 at 12:47
  • 2
    @KenGraham, I think your comment should be converted into a new question. Mar 21, 2017 at 12:51
  • 4
    @JamesJenkins Ok, But I am off to work at the moment, so it will have to wait!
    – Ken Graham
    Mar 21, 2017 at 12:53

4 Answers 4


From Scouting For Girls, Official Handbook of the Girl Scouts

Whistle Signals

  1. One blast, "Attention"; "Assemble" (if scattered).

  2. Two short blasts, "All right."

  3. Four short blasts, calls "Patrol Leaders come here."

  4. Alternate long and short blasts, "Mess Call."

From Scouting for Boys: A Handbook for Instruction in Good Citizenship By Robert Baden-Powell

  1. One long blast means "Silence," "Alert," "Look out for my next signal." Also approaching a station.

  2. Two short blasts means "All right."

  3. A succession of long, slow blasts means "Go out," "Get farther away," or "Advance," "Extend," "Scatter."

  4. A succession of short, sharp blasts means "Rally," "Close in," "Come together," "Fall in," "Danger," "Alarm."

  5. Three short blasts followed by one long one from scout master calls up the patrol leaders--i.e., "Leaders, come here."

Personally, I would avoid using whistle signals in the absence of a genuine emergency because other people might assume that you are having one.

  • Not so sure about longer sequences, or blast-length-based codes, but it's nice to know there's at least a little standardization on 1, 2, and 3-blast meanings.
    – drwestco
    Mar 22, 2017 at 6:45
  • And the guideline about avoiding whistle usage except in case of emergency is well-taken. I can imagine other scenarios being confusing, both for the whistle-blowing party (am I talking with my separated party member, or some other group?), and for others in the area (is this random whistle I'm hearing someone in distress?).
    – drwestco
    Mar 22, 2017 at 6:49
  • So, slightly different calls, for boys and girls, for "patrol leaders come".
    – Martin F
    Mar 23, 2017 at 16:21

Beyond the previously mentioned Scouting communication guidelines, Morse Code is definitely an option. However, Morse code isn't as widely known anymore and could potentially be misinterpreted as a call for help.

Any distance coverable by a whistle in backcountry could also be covered by a two-way radio. Cheap'ish hand-held radios are a staple for the groups I go backpacking with and "check-in" times are pre-established before we set out. We all carry whistles as well, but the general consensus is that we only use the whistle in an emergency.


If anyone has hiked in the woods knows that noise may not travel very far, especially in dense forested areas. So the use of any whistle would imply that group members should be relatively close together.

It is of little importance what "standards" a particular group uses for their whistle signaling for communications, as long as everybody uses the system correctly.

But that said I would be cautious on using a whistle too often in the outdoors.

This is the most important communication item. This affords a chance of self-rescue if one gets lost or separated from the group. A whistle may also be used to attract the attention of rescuers or passers-by. It requires very little effort and energy to blow, yet the sound carries great distances.

Children and immature adults must keep their lips off until an actual emergency. The whistle is a survival tool, not a toy.

All group members should be familiar with distress signaling. A universally-recognized distress code is three equal blasts on the whistle, to be repeated until others hear it and respond with two blasts of recognition. Make sure everyone knows that if possible, the person lost or in distress needs to stay in one place until reunited with the rest of the group.

Another universal distress code is the S.O.S (three short blasts, three long blasts, three short blasts).

Get a whistle that’s worth carrying.

Okay, there are whistles and there are whistles. Forget about kid’s toys and useless, feeble gimmicks. Get a good one, since a life could depend on it. Look for a whistle that’s rated for military, EMS, rescue, or law enforcement work (large, loud, durable, and easy-to-blow).

Put your whistle on a lanyard so you don’t lose it. - Wilderness Survival and Safety


The nice thing about standards is that you have so many to choose from. - Andrew S. Tanenbaum

While there are standards you and your companions need to know and agree upon what that standard is prior to having an issue. That said it's fairly common to understand ongoing whistle blasts to mean something isn't right or HEEEEEEELLLLLLLPPPPPP.

A sampling of standards

The other answers and comments mention some standards for whistles including boy/girl scouts, morse, SOS, triple blast = emergency etc. Also consider boats, trains, even heavy equipment backing up all use various forms of whistle/horn blasts to mean something.

Ambiguity as demonstrated by the whitewater community

I can speak to using whistles in the whitewater environment where 3: emergency but 1 and 2 have different meanings based on which group you are with.

Semi-standard commercial rafting whistle blasts

  1. There is a low level situation, everyone pay attention and help if you can.

  2. The situation is elevated secure your boat and help make a good effort to help.

  3. (3 or more) Dire emergency, walk on water to make the rescue.

Semi-standard private whitewater boater whistle blasts

  1. I'm Ok, or drop clear, or otherwise signaling a positive safe state.

  2. Wait/Be alert. There is an issue but it's not major.

  3. (3 or more) Dire emergency move to the scene of the rescue immediately

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