The Alpine distress signal is a distress signal in the case of mountain emergency, an emergency in alpine areas.
The signal was introduced in 1894 on the suggestion of Clinton Thomas Dent and was soon adopted internationally.
The Alpine distress signal traditionally consists of a signal by blasts from a whistle (may also be an air horn), which is repeated six times in the minute (every ten seconds).
Thus it can be confirmed to the person/party in trouble that its distress signal was received.
Whoever receives distress signals, should confirm and alert the emergency services.