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. 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.
The Emergency Broadcast System (EBS), sometimes called the Emergency Action Notification System (EANS), was an emergency warning system used in the United States. It was the most commonly used, along with the Emergency Override system. It replaced the previous CONELRAD system and was used from 1963 to 1997, at which point it was replaced by the Emergency Alert System.
An emergency position-indicating radiobeacon (EPIRB) is a type of emergency locator beacon for commercial and recreational boats, a portable, battery-powered radio transmitter used in emergencies to locate boaters in distress and in need of immediate rescue. In the event of an emergency, such as a ship sinking or medical emergency onboard, the transmitter is activated and begins transmitting a continuous 406 MHz distress radio signal, which is used by search-and-rescue teams to quickly locate the emergency and render aid. The signal is detected by satellites operated by an international consortium of rescue services, COSPAS-SARSAT, which can detect emergency beacons anywhere on Earth transmitting on the distress frequency of 406 MHz. The satellites calculate the position or utilize the GPS coordinates of the beacon and quickly passes the information to the appropriate local first responder organization, which performs the search and rescue. As Search and Rescue approach the search areas, they use Direction Finding (DF) equipment to locate the beacon using the 121.5 MHz homing signal, or in newer EPIRBs, the AIS location signal. The basic purpose of this system is to help rescuers find survivors within the so-called "golden day" during which the majority of survivors can usually be saved. The feature distinguishing a modern EPIRB, often called GPIRB, from other types of emergency beacon is that it contains a GPS receiver and broadcasts its position, usually accurate within 100 m (330 ft), to facilitate location. Previous emergency beacons without a GPS can only be localized to within 2 km (1.2 mi) by the COSPAS satellites and relied heavily upon the 121.5 MHz homing signal to pin-point the beacons location as they arrived on scene.
The Emergency Alert System (EAS) is a national warning system in the United States designed to allow authorized officials to broadcast emergency alerts and warning messages to the public via cable, satellite and broadcast television and both AM, FM and satellite radio. Informally, Emergency Alert System is sometimes conflated with its mobile phone counterpart Wireless Emergency Alerts (WEA), a different but related system. However, both the EAS and WEA, among other systems, are coordinated under the Integrated Public Alert and Warning System (IPAWS). The EAS, and more broadly IPAWS, allows federal, state, and local authorities to efficiently broadcast emergency alert and warning messages across multiple channels. The EAS became operational on January 1, 1997, after being approved by the Federal Communications Commission (FCC) in November 1994, replacing the Emergency Broadcast System (EBS), and largely supplanted Local Access Alert systems, though Local Access Alert systems are still used from time to time. Its main improvement over the EBS, and perhaps its most distinctive feature, is its application of a digitally encoded audio signal known as Specific Area Message Encoding (SAME), which is responsible for the characteristic "screeching" or "chirping" sounds at the start and end of each message. The first signal is the "header" which encodes, among other information, the alert type and locations, or the specific area that should receive the message. The last short burst marks the end-of-message. These signals are read by specialized encoder-decoder equipment. This design allows for automated station-to-station relay of alerts to only the area the alert was intended for.
Specific Area Message Encoding (SAME) is a protocol used for framing and classification of broadcasting emergency warning messages. It was developed by the United States National Weather Service for use on its NOAA Weather Radio (NWR) network, and was later adopted by the Federal Communications Commission for the Emergency Alert System, then subsequently by Environment Canada for use on its Weatheradio Canada service. It is also used to set off receivers in Mexico City and surrounding areas as part of the Mexican Seismic Alert System (SASMEX).
NOAA Weather Radio (NWR), also known as NOAA Weather Radio All Hazards, is an automated 24-hour network of VHF FM weather radio stations in the United States that broadcast weather information directly from a nearby National Weather Service office. The routine programming cycle includes local or regional weather forecasts, synopsis, climate summaries or zone/lake/coastal waters forecasts. During severe conditions the cycle is shortened into: hazardous weather outlooks, short-term forecasts, special weather statements or tropical weather summaries. It occasionally broadcasts other non-weather related events such as national security statements, natural disaster information, environmental and public safety statements, civil emergencies, fires, evacuation orders, and other hazards sourced from the Federal Communications Commission's (FCC) Emergency Alert System. NOAA Weather Radio uses automated broadcast technology that allows for the recycling of segments featured in one broadcast cycle into another and more regular updating of segments to each of the transmitters. It also speeds up the warning transmitting process.
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:
In telecommunications, radio silence or Emissions Control (EMCON) is a status in which all fixed or mobile radio stations in an area are asked to stop transmitting for safety or security reasons.
Warning system is any system of biological or technical nature deployed by an individual or group to inform of a future danger. Its purpose is to enable the deployer of the warning system to prepare for the danger and act accordingly to mitigate or avoid it.
WCKY-FM is a radio station licensed to Pemberville, Ohio, serving the Toledo market. Owned by iHeartMedia, the station - branded as Buckeye Country 103.7 CKY - features a classic country format.
A weather radio is a specialized radio receiver that is designed to receive a public broadcast service, typically from government-owned radio stations, dedicated to broadcasting weather forecasts and reports on a continual basis, with the routine weather reports being interrupted by emergency weather reports whenever needed. Weather radios are typically equipped with a standby alerting function—if the radio is muted or tuned to another band and a severe weather bulletin is transmitted, it can automatically sound an alarm and/or switch to a pre-tuned weather channel for emergency weather information. Weather radio services may also occasionally broadcast non-weather-related emergency information, such as in the event of a natural disaster, a child abduction alert, or a terrorist attack.
WNFL is an American all-sports radio station located in Green Bay, Wisconsin. The station is locally owned and operated by Midwest Communications, which owns six other stations in Northeast Wisconsin. WNFL simulcasts the programming of WRNW in Milwaukee from 6 a.m. to 6 p.m. on weekdays. The station is also an affiliate of Fox Sports Radio, carrying much of their line-up for the remainder of the day and on weekends. It airs one minute news updates from CBS at approximately 45 minutes past the hour. In addition to the station's sports-talk offerings, WNFL airs Milwaukee Bucks basketball play-by-play and local high school football and basketball games. Milwaukee Brewers baseball games during the work week are also on WNFL, with night and weekend games on sister station WTAQ.
WGU-20 was an emergency government civil defense preparedness radio station in Chase, Maryland, United States, operated by the United States Defense Civil Preparedness Agency in the 1970s.
WKAR-FM is a non-commercial public radio station in East Lansing, Michigan. It is owned by Michigan State University, along with sister stations WKAR and WKAR-TV. They are owned by Michigan State University, with studios are in the Communication Arts and Sciences Building, at Wilson and Red Cedar Roads on the MSU campus.
Weatheradio Canada is a Canadian weather radio network owned and operated by Environment and Climate Change Canada's Meteorological Service of Canada division. Weatheradio Canada is headquartered in Montreal, Quebec and transmits in both official languages from 230 sites across Canada. Weatheradio Canada, as well as Environment Canada's weather telephone service Hello Weather, utilizes Nuance Communications text to speech voices. Starcaster Text to Speech, owned by STR-SpeechTech Ltd, was used from 1994 to 2021.
The National Emergency Alarm Repeater (NEAR) was a civilian emergency warning device in the United States. It was a 2–3" (5–7.5 cm) square box designed to plug into a standard power outlet to receive a special signal sent over the electric power transmission lines. Research and testing for the NEAR program was developed in 1956 during the Cold War to supplement the existing siren warning systems and radio broadcasts in the event of a nuclear attack. The advent of the radio Emergency Broadcast System rendered NEAR obsolete, although a severe disadvantage inherent in the Emergency Broadcast System was that it required a television or radio to be turned on for a household to receive the emergency alarm, whereas NEAR did not. Despite this advantage, upon the introduction of the Emergency Broadcast System, stockpiled NEAR repeaters were destroyed by their respective manufacturers.
A National Emergency Message, formerly known until 2022 as an Emergency Action Notification, is the national activation of the Emergency Alert System (EAS) used to alert the residents of the United States of a national or global emergency such as a nuclear war or any other mass casualty situation. This alert can only be activated by the president of the United States or a designated representative thereof, such as the vice president. The Emergency Broadcast System (EBS) also carried the Emergency Action Notification. No president has ever activated the alert aside from the 2011 national EAS test.
On the morning of January 13, 2018, an alert was accidentally issued via the Emergency Alert System and Wireless Emergency Alert System over television, radio, and cellular networks in the U.S. state of Hawaii, instructing citizens to seek shelter due to an incoming ballistic missile. It concluded with "This is not a drill". The message was sent at 8:08 a.m. local time. The state had not authorized civil defense outdoor warning sirens.
Civ-Alert was the civil defense warning system in the state of Hawaii from 1960 to 1977. Civ-Alert was established in the wake of the tsunami generated by the 1960 Valdivia earthquake on the Chilean coast, which devastated Hilo. Unlike CONELRAD, the warning system in use in the mainland United States, Civ-Alert consisted of the transmission of civil defense information and instructions from a studio at state Civil Defense headquarters in Diamond Head on existing radio station frequencies; this was important, as no one radio station could cover the entire Hawaiian islands. The Civ-Alert system was a major improvement. It led to the redesign of emergency warnings in the mainland U.S. as a similar system, the Emergency Broadcast System (EBS). Civ-Alert was rebranded as EBS in May 1977.
