Warning system

A 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.^{[how?][citation needed]}

A HSS Engineering TWS 295 electronic sirens warning Civil Defense siren.

There are 8,200 alarm sirens for civil protection throughout Switzerland. They are tested once a year, on the first Wednesday in February.^[1] Sound sample^ⓘ

Warning light indicating danger of laser exposure

Warnings cannot be effective unless people react to them. People are more likely to ignore a system that regularly produces false warnings (the cry-wolf effect), but reducing the number of false warnings generally also increases the risk of not giving a warning when it is needed.^[2] Some warnings are non-specific: for instance, the probability of an earthquake of a certain magnitude in a certain area over the next decade. Such warnings cannot be used to guide short-term precautions such as evacuation. Opportunities to take long-term precautions, such as better building codes and disaster preparedness, may be ignored.^{[3][better source needed]}

Early warning siren for earthquakes and floods

Biological warning systems

• Aposematism (e.g. warning coloration)
• Climate canary
• Fear
• Miner's canary
• Pain

Man-made warning systems

• Emergency population warning

Civilian warning systems

A fire alarm that warns people if a building is on fire

• Alberta Emergency Alert
• Alberta Emergency Public Warning System (replaced by Alberta Emergency Alert)^[4]
• Alert Ready (Canada)
• Automatic Warning System
• Child abduction alert system
• Dam safety system
• Earthquake warning system
• Emergency Alert System (EAS) (United States)
• Famine Early Warning Systems Network
• Federal Civil Defense Authority
• Fire alarm system
• Gale warning
• Ground proximity warning system
• Indian Ocean Tsunami Warning System
• International Early Warning Programme
• J-Alert (Japan)
• Lane departure warning system
• National Severe Weather Warning Service
• N.E.A.R. (National Emergency Alarm Repeater)
• North Warning System
• Standard Emergency Warning Signal (Australia)
• Traffic Collision Avoidance System
• Train Protection & Warning System
• Tsunami warning system

Military warning systems

Historical beacon-based systems:

• Byzantine beacon system in Asia Minor during the 9th century

Space-based missile early warning systems:

• Defense Support Program (United States, to be succeeded by the "Space-Based Infrared System")
• Space-Based Infrared System (SBIRS) (United States)
• Oko, also known as "SPRN" (Russia)

Airborne early warning systems:

• Airborne Early Warning and Control ("AWACS" for NATO, many countries have developed their own AEW&C systems)

Ground-based early warning radar systems:

• Ballistic Missile Early Warning System and PAVE PAWS (United States)
• Duga radar, also known as the "Russian Woodpecker" (Russia)
• Dnestr radar (1st generation Russian)
• Daryal radar (2nd generation Russian)
• Voronezh radar (3rd and current generation Russian)
• Chain Home (British, now defunct)
• Chain Home Low (British, now defunct)
• ROTOR (British, now defunct)

Optical sensors:

• Bomb Alarm System

Emergency broadcasting:

• CONELRAD (United States, succeeded by the Emergency Broadcast System)
• Emergency Broadcast System (EBS) (United States, succeeded by the Emergency Alert System)

See also

• Alarm (disambiguation)