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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.
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.
A tornado warning is a public warning that is issued by weather forecasting agencies to an area in the direct path of a tornado, or a thunderstorm capable of producing one, and advises individuals in that area to take cover. Modern weather surveillance technology such as Doppler weather radar can detect rotation in a thunderstorm, allowing for early warning before a tornado develops. They are also commonly issued based on reported visual sighting of a tornado, funnel cloud, or wall cloud, typically from weather spotters or the public, but also law enforcement or local emergency management. When radar is unavailable or insufficient, such ground truth is crucial. In particular, a tornado can develop in a gap of radar coverage, of which there are several known in the United States.
A severe thunderstorm watch is a statement issued by weather forecasting agencies to advise the public that atmospheric conditions in a given region may lead to the development of severe thunderstorms within the region over several hours. The criteria for issuing a watch varies from country to country and may also include torrential rainfall and tornadoes. A watch may also be issued several hours ahead of the arrival of a mature and organized complex of storms, such as a mesoscale convective system.
A severe thunderstorm warning is a type of public warning for severe weather that is issued by weather forecasting agencies worldwide when one or more severe thunderstorms have been detected by Doppler weather radar, observed by weather spotters, or reported by an emergency management agency, law enforcement, or the general public. Unlike a watch, a warning is issued to areas in the direct path of active severe thunderstorms, that are expecting a direct impact typically within an hour. Severe thunderstorms can cause property damage and injury due to large hail, high winds, and flooding due to torrential rainfall. The exact criteria to issue a warning varies from country to country.
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.
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:
A flash flood warning is a severe weather warning product of the National Weather Service that is issued by national weather forecasting agencies throughout the world to alert the public that a flash flood is imminent or occurring in the warned area. A flash flood is a sudden, violent flood after a heavy rain, or occasionally after a dam break. Rainfall intensity and duration, topography, soil conditions, and ground cover contribute to flash flooding.
In weather forecasting in the United States, "particularly dangerous situation" (PDS) is enhanced wording used by the National Weather Service to convey special urgency in some watch or warning messages for unusually extreme and life-threatening severe weather events, above and beyond the average severity for the type of event. It is used in the format "This is a particularly dangerous situation..." at the discretion of the issuing forecaster. A watch or warning bearing the phrase is referred to as a PDS watch or PDS warning as shorthand jargon.
A tornado emergency is an enhanced version of a tornado warning, which is used by the National Weather Service (NWS) in the United States during imminent, significant tornado occurrences in highly populated areas. Although it is not a new warning type from the NWS, issued instead within a severe weather statement or in the initial tornado warning, a tornado emergency generally means that significant, widespread damage is expected to occur and a high likelihood of numerous fatalities is expected with a large, strong to violent tornado.
An extreme wind warning is an alert issued by the National Weather Service for areas that will experience sustained surface winds 100 knots or greater within one hour, due to a landfalling tropical cyclone. Extreme wind warnings are intended to provide guidance to the general public at a county or sub-county level when such winds pose a significant threat of casualties. Their issuance is intended to cover as precise of an area as possible and can be issued no earlier than two hours before the onset of extreme winds. The extreme wind warning should not be confused with tornado warnings, which covers rotating supercells from severe storms, and high wind warnings, which is similar, but used for non-severe/tornadic winds of 40 mph to 114 mph, mainly on land.
A fire warning is a warning issued through the Emergency Alert System (EAS) in the United States by civil authorities to inform the public of major, uncontrolled fires threatening populated areas and/or major roadways. A red flag warning will generally precede any fire activity by at least one to two days. A fire warning will generally include information on the location and movement of the fire, evacuation instructions, and shelter locations.
J-Alert is the early warning system used in Japan. J-Alert was launched in February 2007. The system is designed to quickly inform the public of threats and emergencies such as earthquakes, severe weather, and other dangers. The system was developed in the hope that early warnings would speed up evacuation times and help coordinate emergency response.
Wireless Emergency Alerts, is an alerting network in the United States designed to disseminate emergency alerts to mobile devices such as cell phones and pagers. Organizations are able to disseminate and coordinate emergency alerts and warning messages through WEA and other public systems by means of the Integrated Public Alert and Warning System.
Evacuation immediate is a warning issued through the Emergency Alert System (EAS) in the United States to notify the public of a mandatory evacuation due to a wildfire, approaching hurricane, or an imminent explosion due to a gas leak. It is typically issued by a local or state authority and is relayed by the National Weather Service. The warning can replace a Civil Emergency Message, Fire Warning, or other warnings when required.
A law enforcement warning is a warning issued through the Emergency Alert System (EAS) in the United States to warn the public of criminal events that pose a threat to public safety. These include jailbreaks, riots, and bomb explosions. An authorized law enforcement agency may blockade roads, waterways, or facilities, evacuate or deny access to affected areas, and arrest violators or suspicious persons. The warning is usually issued by a law enforcement agency and is relayed by the National Weather Service.
A civil emergency message is a warning issued through the Emergency Alert System (EAS) in the United States to warn the public of a significant in-progress or imminent threat or danger to public safety. It is typically issued by a local or state authority and is relayed by the National Weather Service. The warning is a higher priority than a local area emergency (LAE), but it's less specific than a civil danger warning (CDW). For example, the warning could be used to describe an alert issued by the National Terrorism Advisory System.
Local area emergency is an advisory issued by local authorities through the Emergency Alert System (EAS) in the United States to notify the public of an event that does not pose a significant threat to public safety and/or property by itself, but could escalate, contribute to other more serious events, or disrupt critical public safety services. Instructions, other than public protective actions, may be provided. Examples include: a disruption in water, electric or natural gas service, road closures due to excessive snowfall, or a potential terrorist threat where the public is asked to remain alert.
On February 11, 2013, the Emergency Alert System of five different television stations across the U.S. states of Montana, Michigan, Wisconsin, and New Mexico were hijacked, interrupting each television broadcast with a Local area emergency message warning viewers of a zombie apocalypse. The message was subsequently declared as a hoax by local authorities and was reported to be a result of hackers gaining access to the Emergency Alert System equipment of various television stations.
References
- ↑ WTVD (2018-01-13). "See the warning Hawaiians saw on TV during missile scare". ABC11 Raleigh-Durham. Retrieved 2021-02-20.
- ↑ "Civil Danger Warning". YouTube. February 1, 2011.
- ↑ "Civil Danger Warning on May 27, 2019". Iowa Environmental Mesonet. May 27, 2019.
- ↑ "Civil Danger Warning on Aug 10, 2021". Iowa Environmental Mesonet. Aug 10, 2021.
