Civil defense signals

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Civil defense signals are signals that should reach a large number of people as quickly as possible. In a broader sense, they can be warnings, alarms or all-clears.

There is a civil defense test alarm for the system, which regularly tests its functionality.


Warning options are important both for civil major incidents (natural disasters such as floods , incidents such as chemical or reactor accidents, NBC alarm ) and for military cases (armed attack on a state).


Nationwide warning day

On September 10, 2020 - for the first time after reunification - a nationwide test alarm will be carried out again. In future, this will take place on the second Thursday in September of each year, including all warning channels ( MoWaS , warning apps , siren signals, radio, etc.).

With the uniform nationwide warning day, the population is to be sensitized and prepared for possible danger situations such as natural or environmental disasters and major fires. The warning apps will then hit all over Germany, sirens will wail and broadcasters will interrupt their broadcasts.

Types of transmission of civil defense signals

There are several ways to broadcast civil defense signals (especially disaster warnings).

Options for large-scale disaster warnings differ in terms of speed, the achievable size of the population, failover, and fixed and variable costs. However, special attention is paid to the “wake-up effect”, i.e. the possibility of drawing the population's attention to certain media and their messages. Accordingly, new developments are such that receiving devices activate themselves in the event of a disaster.

Mechanical siren
Sound sample for a typical civil defense siren E57 (Hamburg, 2016)
Siren trailer (SLEA) of the civil defense , Germany, ca.1950
Signals via sirens
A nationwide, centrally controlled siren network offers a simple and inexpensive option. The alarm via siren signals is usually faster than a warning via radio and television, can be localized more easily and also reaches people who are not currently receiving any radio media (alarm function). In the case of radio transmissions of the siren triggering, any power failures must also be taken into account and the corresponding emergency power supplies such as batteries must be provided. While Austria has a comprehensive siren network to this day, there was such a network in West Germany from the 1950s to the 1990s to notify everyone.
Radio and television
Already connected to the German modular warning system (MoWaS for short, formerly SatWaS) are a large number of TV and radio stations (also in connection with RDS and DAB ) and some Internet providers who can distribute the latest warnings accordingly. The wake-up effect is missing, however. In the event of a power failure, radio announcements are practically useless, as very few households are equipped with network-independent receivers (apart from car radios and smartphones with VHF receivers).
Mass short messages
In most countries, mobile radio technology is not designed for such capacities. Tests in Germany had shown that it took up to 24 hours to warn 50,000 residents of a city via SMS. One solution would be to use the cell broadcast of the GSM network or the service area broadcast of UMTS . With this, 80% of the population could be warned of dangers inexpensively, quickly and locally.
Landline phone
The greatest range can still be achieved without sirens via the telephone , which also has a wake-up effect. The fixed network has the necessary capacity to handle several thousand calls simultaneously. Installation of alarm computers in the exchanges is necessary for this. In Germany this would cost around 200 million euros. However, the number of landline connections is decreasing . It should also be taken into account that many small domestic telephone systems already require an external power supply, which means that this option may also be ruled out.
Cellular telephones
The technology is currently not designed for such capacities. The emergency power supply for the transmitters (radio cells), which is not always available, must also be taken into account.
Radio clock transmitter DCF77 , radio alarm clock
In 2003, the Federal Office of Administration, Central Office for Civil Protection, provided brief information about the research project with field protection to warn the public with the radio alarm clock. From October 13th to December 10th, 2003, 39 alarms were sent in a test with 1,000 recipients across the country. In 2007, the German Institute for Standardization was commissioned to work with industry to create a draft standard "Population warning by radio alarm using DCF77". To date, this technology has not been implemented for use by the population.
Warning apps
Since June 2015, the Federal Office for Civil Protection and Disaster Assistance (BBK) has been offering a warning app called NINA (short for "Emergency Information and News App"), which provides warnings in the area of ​​civil protection both from the so-called modular warning system (MoWaS ) as well as from the German Weather Service and the Federal Waterways and Shipping Administration. In contrast to Android users, some iPhone users find the fact that there is no location reference for the warning messages and the warning messages are published throughout Germany as annoying.
The KATWARN smartphone app , which was developed by the Fraunhofer Institute for Open Communication Systems and public insurers, has been available since 2012 . KATWARN obtains its information both from the German Weather Service and from the disaster control teams of the associated cities, districts and city states. About KATWARN the user only location-based warnings. The user can specify different fixed locations for which he would like to receive warnings or choose the "guardian angel function", in which his current location is constantly tracked via GPS.
It is critical to see that there is currently no nationwide uniform warning app. While some cities, counties and countries use the NINA warning app , others rely on KATWARN . As a result, the user, if he is regularly in different places in Germany, is forced to install both apps. Furthermore, the warning network still has large gaps, as the municipalities, rural districts and federal states are not yet using warning apps across the board. LevelAlarm has been established as a uniform warning app for floods since 2015 . The level alarm system collects and standardizes water data such as water level and runoff from Germany, Austria, Switzerland, South Tyrol, Slovakia, Great Britain, Ireland, Slovenia and since 2019 also the USA. The warning can be set individually by the user to a definable water level limit value. If this value is reached or exceeded, warning signals are given by a push message, ring tones, vibration and flashing of the smartphone flash. The development and operation are supported by the Austrian Federal Ministry for Sustainability and Tourism .


At the beginning of the 1950s, efforts were made in Germany to reorganize civil protection and disaster control . This also included the establishment of warning offices in the Federal Republic of Germany as well as the establishment and expansion of a comprehensive alarm system to warn of disasters . The possibility of comprehensive warning and alarming was achieved with the installation of sirens . These included the E57 siren model , but also so-called high-performance sirens that were installed in larger cities such as Saarbrücken or Kassel .

Until the end of the Cold War , the sirens were tested twice a year in a test alarm (in West German territory). This took place on a Wednesday in March and September around 10 a.m. First a one-minute continuous tone, then an air alarm or ABC alarm and finally another continuous tone was triggered.

The siren network of 80,000 sirens in Germany was heavily thinned out in 1993 for cost reasons due to the discontinuation of the warning offices of the civil protection warning service and ultimately 40,000 sirens were dismantled. The cities took over some of the sirens from the federal government and have since had to maintain the sirens themselves. In isolated cases, sirens were left to be used for alarming the fire brigade . Since then there has been no comprehensive system for alerting the population with a wake-up function. The Federal Office for Civil Protection and Disaster Relief is looking for a new medium for this.

Siren network available today

Today, only a few major German cities have an intact siren network made up of high-performance sirens. These include Aachen , Augsburg , Bonn , Darmstadt , Dresden , Duisburg , Düsseldorf , Erlangen , Hagen , Hamm , Hoyerswerda , Karlsruhe , Kassel , Cologne , Krefeld , Mannheim , Mainz , Moers , Norderstedt , Pforzheim , Solingen , Saarbrücken , Wiesbaden and Wuppertal . The Hanseatic City of Hamburg has a siren network specially designed to warn of storm surges .

There are still around 15,000 sirens nationwide that can be used to send a 1-minute howling sound.

Functional tests of the sirens are handled differently by the cities and municipalities; for example, tests are carried out once a year in Düsseldorf and on the second Wednesday of every quarter in Dresden.

The picture is very different in the individual counties . For example, in the Steinfurt district there is still a coherent siren network and a mobile system that is tested once a month. In Saarland there are sirens in many municipalities, which are mainly used to alert the fire brigade. The sirens are usually tested every Saturday at 12 noon. In Bavaria , siren warning systems are installed in all locations within a radius of 25 kilometers around all nuclear power plants in order to alert the population in the event of a serious incident. You will be tested at least twice a year.

In the meantime, many municipalities such as For example, the districts of Recklinghausen or Minden-Lübbecke and the city of Osnabrück have again introduced a siren system to reach citizens in the danger area with a warning. The loud and shrill sound of a siren is an effective means of clearly audible at least the existence of a danger for people in the vicinity.

Civil defense signals used

There are no longer any national siren signals since the old civil protection network was dismantled. The definition of siren signals is currently the responsibility of the disaster control authorities of the federal states.

Alarm until around 1975
Alarm since about 1975
Howling sound that increases and decreases for one minute

In Germany only one disaster warning and alarm signal is used. Until around 1975 this was a two-minute signal consisting of three 12-second continuous tone with a 12-second pause, followed by a 60-second continuous tone. Since the beginning of this signal sequence resembles that of the volunteer fire brigades and mix-ups are to be avoided, a one-minute rising and falling howling sound (formerly known as an air alarm) has been used in Germany as a "warning the population" since then. The signal generally means “switch on the radio and listen to announcements”. The radio is then used to send out more precise instructions on how to behave for citizens on certain stations (usually the public service program with traffic radio or regional stations ). As the signal is not available nationwide, it sometimes has different meanings, such as B. that closed rooms are to be visited, windows and doors closed and air conditioning systems to be switched off.

As a second siren signal, a one-minute continuous tone is set up to give the all-clear, which is given after the end of the hazardous situation.


Austria has a nationwide, operational network of 8,212 sirens (as of October 6, 2018) .

Siren warning system

There are three different general signals: warning, alarm, all-clear . It is not clear from the warning and alarm signs what kind of disaster it is. This can only be learned from the special ORF news broadcast at the same time and behavioral measures that are announced via mass media (radio, television and the Internet). In the case of only local alarms, the message can also be given through loudspeaker announcements, for example by the fire brigade.

In addition, the fire brigade alarm can be given via the system. The use of the alarm signal depends on the individual fire service . If, for example, a fire brigade alerts its members mainly using radio receivers , the siren signal ( fire brigade alarm sound of a motor siren ? / I alarm sound of a high-performance siren ? / I ) is rarely used, as in many cities and large towns. In many fire brigades, however, a distinction is also made between using both to alert in the event of a fire or rescuing people , whereas in technical operations only the radio pagers are used. This depends on the local alarm plans . Audio file / audio sample Audio file / audio sample

There is a weekly siren rehearsal (a 15-second continuous tone) with the siren rehearsal signal every Saturday around 12 noon; The different triggering routes - federal warning center ( BWZ), state warning centers (LAWZ) , district alarm and warning centers (BAWZ) or direct triggering - are tested alternately.

Since 1998, an Austria-wide siren rehearsal with all disaster signals has taken place once a year on the first Saturday in October between 12:00 and 13:00 . This will be announced in advance in the mass media. Functionality is checked on the one hand, and audibility on the other. At the same time, the aim is to raise awareness among the population. Although triggered centrally, all fire brigades are involved, which carry out the reports. Because the sirens are triggered by the individual alarm centers during the weekly rehearsal, it is not technically possible for radio technology to trigger all of them at the same time, so that the rehearsal alarm times are not uniform across Austria to the minute. In some cases, nationwide test alarms are carried out independently, as in Styria . In addition, regionally dependent tests, such as a dam warning in the Maltatal , are also carried out together with the nationwide siren sample .

Civil defense and test signals used

Every Saturday a test alarm from a motor siren of the fire brigade in Austria (recording from a good 10 m distance).

The siren test is only a 15-second continuous tone (a particularly short alarm tone). It takes place across Austria every Saturday at around 12:00 noon, depending on the location.

The fire brigade alarm consists of three 15-second continuous tone with two 7-second pauses in between.

Warning (siren test on October 5, 2019) in Austria 3 minutes continuous tone. (Shot from a good 10 m distance).

Approaching danger (warning) is announced with a three-minute continuous tone. The population is asked to turn on the radio or television and to observe the instructions published there.

Alarm (siren rehearsal on October 5, 2019) in Austria 1 min up and down. (Shot from a good 10 m distance).

The signal danger (alarm) consists of a rising and falling tone lasting one minute and means immediate danger: go to protective premises (a car does not provide sufficient protection), follow the behavioral measures communicated via the media and switch on the radio.

All clear (siren test on October 5, 2019) in Austria 1 minute continuous tone. (Shot from a good 10 m distance).

The end of the danger (all-clear) is indicated by a one-minute continuous tone. Possible restrictions for the normal daily routine are disseminated through the media.

Other ways of alerting the civilian population

Since 2017, the Ministry of the Interior has been offering the option of individual alarms based on location or events via an installed mobile app , SMS , email or other IT options of the KATWARN Österreich / Austria system .


In South Tyrol, Austria only partially adopted the alarm system in 2002. The system point warning was not accepted. They can be triggered from the regional emergency call center in Bolzano .


In Switzerland , the Federal Office for Civil Protection (FOCP) and the National Alarm Center (NAZ) are responsible for alerting people. It broadcasts warnings via radio, television, sirens and in the event of natural hazards via on the Internet.


Rules of conduct at the General Alarm
play ? / iAudio file / audio sample
Conduct the water alarm
alert play ? / iAudio file / audio sample

Switzerland has around 7200 civil defense sirens , 5000 of which are permanently installed (600 of which are also used for water alarms) and 2200 can be attached to vehicles.

The sirens are triggered by the cantonal or local authorities. The stationary sirens can be activated remotely. The sirens are tested every year on the first Wednesday in February between 1.30 p.m. and 3 p.m. with the "general alarm" signal.

Since April 1, 2004, there have only been two alarm signals in Switzerland: the general alarm and the water alarm . The earlier characters C-alarm and radiation alarm have been removed. In addition, alerting the fire brigades ( Cis-Gis signal) with civil defense sirens is no longer permitted.

General alarm
Regular ascending and descending tone of the sirens lasting one minute. After an interruption of two minutes, the alarm is repeated. When the general alarm sounds, the population should turn on the radio and follow the instructions of the authorities.
Water alarm
The water alarm sounds only in endangered areas below dams . It consists of twelve deep continuous tones of 20 seconds each at 10-second intervals. When the water alarm sounds, the population should leave the endangered area, then turn on the radio and follow the instructions of the authorities.

Mass media

The official warnings are distributed via the TV and radio programs of SRG SSR . This has an emergency disposition ( Information Catastrophe Alarme Radio Organization , ICARO) and several protected radio transmission systems with increased transmission power, whose signals can also be received in the event of a shelter being occupied.


With the Polyalert project of the BABS, the sirens and their controls were renewed in 2015. It also enables alarms to be triggered via calls and short messages to mobile phone users in the danger zone, via loudspeakers in public transport and via computer screens in companies.


There are 338 sirens nationwide in Luxembourg , which can be triggered individually, per location, municipality, region or nationwide. Outside the city of Luxembourg, a siren test is carried out every first Monday of the month at 12:00.

This information can be found on the inside cover of the Luxembourg telephone books.


The siren network in Denmark consists of 1078 sirens that can warn about 80% of the population. They are tested silently every night. A test with signal takes place every first Wednesday in May at 12:00.

European approximation

There are also different meanings for signals that sound the same within the EU. For example, the increasing and decreasing howling tone is a pre-alarm for one minute in Luxembourg, and the main alarm in Austria and Switzerland in the event of acute danger. In 1999, the German Federal Office for Civil Protection recommended a “study into the development of a uniform siren signal and related recommendations for behavior”.

In English, the terms Reverse 112 or Public Warning Service (PWS) are also used for civil defense signals, especially those that are sent to cell phones.


Web links

Commons : civil defense signals by country  - collection of images, videos and audio files

Individual evidence

  1. Service portal. In: Federal Office for Civil Protection and Disaster Assistance, accessed on August 16, 2020 .
  2. 210th meeting of the Conference of Interior Ministers (June 12-14, 2019 in Kiel), Item 46. Retrieved on May 27, 2020 .
  3. ^ A project by the Federal Office for Civil Protection and Disaster Relief. POPULATION WARNING, accessed September 7, 2020 .
  4. ↑ Inform quickly in the event of a disaster / Immediate emergency - alerting via digital radio thanks to "Emergency Warning Functionality" (EWF) ( Memento from August 27, 2014 in the Internet Archive ) (PDF)
  5. Population warning with the radio alarm clock, brief information about the system and the field test. (PDF; 218 kB) In: Federal Office of Administration, Central Office for Civil Protection, October 1, 2003, accessed on May 17, 2016 .
  6. Dirk Piester, Peter Hetzel, Andreas Bauch: Time and normal frequency distribution with DCF77. (PDF; 3.1 MB) 10 Conclusion. In: PTB-Mitteilungen 114, Issue 4. Physikalisch Technische Bundesanstalt, 2004, p. 365 , accessed on May 17, 2016 : “Between October 13 and December 10, 2003, a total of 39 sharp test alarms were sent, which are registered with 1000 receivers spread across the country should. Modified, commercially available radio-controlled clocks (wristwatches, alarm clocks, wall clocks, PC radio-controlled clocks) were used which, in addition to their standard function, could alarm optically and acoustically. The participants in the field test had undertaken to report the alarms, including false alarms, via the Internet. In the final report now available, HKW showed that the alarm time and the probability of receiving the radio alarm are equally good in our country. "
  7. DCF77 in the population warning. In: May 12, 2015, accessed May 17, 2016 .
  8. ^ Federal Office for Civil Protection and Disaster Assistance - Questions & Answers NINA 2.0. Retrieved May 3, 2018 .
  9. Customer reviews on the app on iTunes. Retrieved February 1, 2016 .
  10. KATWARN - Disaster Warning System for the Free and Hanseatic City of Hamburg. Retrieved February 1, 2016 .
  11. Siren signals and population warning. Retrieved February 1, 2016 .
  12. Level alarm - warning of high water. Retrieved October 21, 2019 .
  13. ^ Franz-Josef Sehr : Development of fire protection . In: Freiwillige Feuerwehr Obertiefenbach e. V. (Ed.): 125 years of the Obertiefenbach volunteer fire brigade . Reference 2005, ISBN 978-3-926262-03-5 , pp. 114-119 .
  14. Federal Office for Civil Protection and Disaster Assistance - Warning the population. Retrieved September 13, 2018 .
  15. SZ: Article on the function and warning signals of the siren system that was re-established as a result of the "flood of the century" (accessed on June 9, 2011)
  16. Westfälischer Anzeiger: Siren warning system for Hamm is improved
  18. ^ Website of the city of Mannheim
  19. Storm surge: Leaflet for the population, page 5 (PDF)
  20. Federal Office for Civil Protection and Disaster Assistance - Warning the population. Retrieved September 13, 2018 .
  21. ^ Dresden TV: Article on the siren test on July 9, 2008 (accessed on July 14, 2010)
  22. siren exercise in Steinfurt | Steinfurt district. Retrieved May 3, 2018 .
  23. Sirens. Retrieved September 13, 2018 .
  24. Osnabrück lacks sirens for nationwide warning day. September 3, 2020, accessed September 7, 2020 .
  25. Which valid siren signals are there in Germany? ; accessed on November 23, 2018
  26. ^ Peer Rechenbach: Information, warning and alerting the population . In: Harald Karutz, Wolfram Geier, Thomas Mitschke (eds.): Civil protection . Springer Berlin Heidelberg, Berlin, Heidelberg 2017, ISBN 978-3-662-44634-8 , pp. 252 , doi : 10.1007 / 978-3-662-44635-5 ( [accessed May 15, 2020]).
  27. Which valid siren signals are there in Germany? (No longer available online.) In: Website of the Federal Ministry of the Interior. Archived from the original on May 17, 2016 ; accessed on May 17, 2016 .
  28. Civil defense test alarm ( memento of October 4, 2015 in the Internet Archive ) , page of the civil defense association (updated content)
  29. ^ Civil protection alarm from the Admont fire brigade, accessed on October 5, 2013.
  30. Test of the dam warning in Upper Carinthia from 2017, accessed on December 3, 2019.
  31. accessed on November 7, 2017
  32. Technical report on the alarm (PDF; 18 kB) accessed on February 7, 2013
  33. ↑ State emergency call center . Site of the Department of Fire and Civil Protection; Retrieved February 7, 2013
  34. ^ The alerting of the population , BABS; accessed April 4, 2020
  35. Federal Office for Civil Protection FOCP:
  36. NZZ of November 7, 2019: Alarm sirens are ripe for the museum and are still indispensable
  37. a b The sirens to alert the population , BABS; accessed April 4, 2020
  38. Radio announcement for the siren test
  39. ICARO and IBBK. Retrieved May 3, 2018 .
  40. When the mobile phone becomes a siren . In: NZZ , May 4, 2012
  41. ↑ FOCP media release on the siren test on February 6, 2016 , from January 28, 2016
  42. Siren warning ( Memento of May 30, 2009 in the Internet Archive ) (PDF)