All clear is the signal, generally given by a civil defence siren, which indicates that an air raid or other hazard has finished and that it is safe for civilians to leave their shelters; it is commonly used in radios as well.
All clear is the signal, generally given by a civil defence siren, which indicates that an air raid or other hazard has finished and that it is safe for civilians to leave their shelters; it is commonly used in radios as well.
During the First World War, the Metropolitan Police introduced their first air raid warning system in London in 1917, which consisted of police officers detonating maroons (a type of loud firework) and the "all clear" was sounded by Boy Scout buglers. [1]
Immediately before the Second World War, a network of sirens had been established in towns across the United Kingdom; the "alert" was given by a rising and falling tone and the "all clear" by a continuous tone. [2] The sirens remained in place during the Cold War but instead of being the responsibility of local police forces, the alarms were activated by the United Kingdom Warning and Monitoring Organisation. Following an air raid, the "all clear" would only be sounded if no nuclear weapons had been used, or when any nuclear fallout was deemed by the Royal Observer Corps to have reached safe levels, which might have been up to two weeks later. The system was discontinued in 1992. [3]
The following is a list of countries that use All Clear on sirens:
Civil defense or civil protection is an effort to protect the citizens of a state from human-made and natural disasters. It uses the principles of emergency operations: prevention, mitigation, preparation, response, or emergency evacuation and recovery. Programs of this sort were initially discussed at least as early as the 1920s and were implemented in some countries during the 1930s as the threat of war and aerial bombardment grew. Civil-defense structures became widespread after authorities recognised the threats posed by nuclear weapons.
A civil defense siren, also known as an air-raid siren or tornado siren, is a siren used to provide an emergency population warning to the general population of approaching danger. It is sometimes sounded again to indicate the danger has passed. Some sirens, especially within small municipalities, are also used to alert the fire department when needed. Initially designed to warn city dwellers of air raids during World War II, they were later used to warn of nuclear attack and natural disasters, such as tornadoes. The generalized nature of sirens led to many of them being replaced with more specific warnings, such as the broadcast-based Emergency Alert System and the Cell Broadcast-based Wireless Emergency Alerts and EU-Alert mobile technologies.
CONELRAD was a method of emergency broadcasting to the public of the United States in the event of enemy attack during the Cold War. It was intended to allow continuous broadcast of civil defense information to the public using radio stations, while rapidly switching the transmitter stations to make the broadcasts unsuitable for Soviet bombers that might attempt to home in on the signals.
Air Raid Precautions (ARP) refers to a number of organisations and guidelines in the United Kingdom dedicated to the protection of civilians from the danger of air raids. Government consideration for air raid precautions increased in the 1920s and 30s, with the Raid Wardens' Service set up in 1937 to report on bombing incidents. Every local council was responsible for organising ARP wardens, messengers, ambulance drivers, rescue parties, and liaison with police and fire brigades.
Protect and Survive was a public information campaign on civil defence. Produced by the British government between 1974 and 1980, it intended to advise the public on how to protect themselves during a nuclear attack. The campaign comprised a pamphlet, newspaper advertisements, radio broadcasts, and public information films. The series had originally been intended for distribution only in the event of dire national emergency, but provoked such intense public interest that the pamphlet was published, in slightly amended form, in 1980. Due to its controversial subject, and the nature of its publication, the cultural impact of Protect and Survive was greater and longer-lasting than most public information campaigns.
A long-range acoustic device (LRAD), acoustic hailing device (AHD) or sound cannon is a specialized loudspeaker that produces sound at high power for communicating at a distance. It has been used as a method of crowd control, which has caused permanent hearing damage, having an extremely high decibel capacity. Other uses have included for negotiations in siege situations to deal with piracy at sea; for mass notification during natural disasters or other emergencies; and by defense forces, including several navies.
A siren is a loud noise-making device. Civil defense sirens are mounted in fixed locations and used to warn of natural disasters or attacks. Sirens are used on emergency service vehicles such as ambulances, police cars, and fire engines. There are two general types: mechanical and electronic.
Royal Air Force Fylingdales or more simply RAF Fylingdales is a Royal Air Force station on Snod Hill in the North York Moors, England. Its motto is "Vigilamus". It is a radar base and is also part of the Ballistic Missile Early Warning System (BMEWS). As part of intelligence-sharing arrangements between the United States and United Kingdom, data collected at RAF Fylingdales are shared between the two countries. Its primary purpose is to give the British and US governments warning of an impending ballistic missile attack. A secondary role is the detection and tracking of orbiting objects; Fylingdales is part of the United States Space Surveillance Network. As well as its early-warning and space-tracking roles, Fylingdales has a third function – the Satellite Warning Service for the UK. It keeps track of spy satellites used by other countries, so that secret activities in the UK can be carried out when they are not overhead. The armed services, defence manufacturers and research organisations, including universities, take advantage of this facility.
The four-minute warning was a public alert system conceived by the British Government during the Cold War and operated between 1953 and 1992. The name derived from the approximate length of time from the point at which a Soviet nuclear missile attack against the United Kingdom could be confirmed and the impact of those missiles on their targets. The population was to be notified by means of air raid sirens, television and radio, and urged to seek cover immediately. In practice, the warning would have been more likely three minutes or less.
An emergency population warning is a method where by local, regional, or national authorities can contact members of the public to warn them of an impending emergency. These warnings may be necessary for a number of reasons, including:
The United Kingdom Warning and Monitoring Organisation (UKWMO) was a British civilian organisation operating to provide UK military and civilian authorities with data on nuclear explosions and forecasts of fallout across the country in the event of nuclear war.
Emergency vehicle equipment is any equipment fitted to, or carried by, an emergency vehicle, other than the equipment that a standard non-emergency vehicle is fitted with.
The Coventry Blitz or Coventration of the city was a series of bombing raids that took place on the British city of Coventry. The city was bombed many times during the Second World War by the German Air Force (Luftwaffe). The most devastating of these attacks occurred on the evening of 14 November 1940 and continued into the morning of 15 November.
The Wartime Broadcasting Service is a service of the BBC that is intended to broadcast in the United Kingdom either after a nuclear attack or if conventional bombing destroyed regular BBC facilities in a conventional war. It is unclear if the Wartime Broadcasting Service is still operational as plans are kept mainly secretly with the BBC and government officials. According to an article by the BBC, recordings of a nuclear attack warning are still re-recorded and kept up to date periodically.
Civil defense in Israel deals with a variety of military and terrorist threats to the civilian population, which have included concealed bombs such as suicide bombings and car bombs, projectiles such as missiles, rockets and mortars, and hijacking of aircraft, buses and buildings. Threats have originated in all countries and territories bordering Israel, as well as Iraq, and an Israeli civil airliner was attacked with missiles in Kenya. Perceived threats that have not materialized to date include sustained interruption of the economy, nuclear attack from Iran, and chemical or biological attack from Iraq or elsewhere.
The Public Warning System (PWS) is a network of civil defense sirens installed by the Singapore Civil Defence Force on over 2,000 strategic points in Singapore to warn Singaporeans of impending dangers, air raids and atomic bomb blasts. Thus far, the siren network has only been used for occasional public awareness drills, monthly noon chimes and for commemorating the island's Total Defence (February 15) and Civil Defence Days (September 15). It was also used to mark a minute's silence nationwide for the passing of former prime minister Lee Kuan Yew on the evening of 23 March 2015 and on 1 and 9 August 2020 to mark the first National Day at home.
The siren suit is a one-piece garment for the whole body which can easily be put on or taken off, originally designed for use on the way to, and in, air-raid shelters. The suit solved the problems of warmth and modesty encountered when seeking shelter during nighttime air raids in the United Kingdom during World War II. It was roomy and could be put on over night clothes quickly when an imminent air raid was announced by the sirens.
A firefighting apparatus or firefighting appliance describes any vehicle that has been customized for use during firefighting operations. These vehicles are highly customized depending on their needs and the duty they will be performing. These duties can include firefighting and emergency medical services.
Canadian Line Materials LTD. (CLM) was a Canadian siren manufacturing company which built civil defense sirens. These sirens were built and installed all over Canada to warn residents and military about incoming nuclear attacks from the USSR during the Cold War.
The Thunderbolt is a discontinued mechanical outdoor warning siren made by Federal Signal Corporation. It has a very recognizable design, being a unidirectional siren with a large yellow exponential horn.
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