Terror alert system

Terror alert systems are standardised emergency population warning systems for describing and disseminating information about terrorism-related threats. They became more popular after the September 11 attacks on the United States in 2001.


National Counter-Terrorism Alert Level

  • Certain - terrorist attack is imminent or has occurred
  • Expected- terrorist attack is highly likely
  • Probable - terrorist attack is likely
  • Possible - terrorist attack could occur
  • Low - terrorist attack is not expected

Administered by the Federal Attorney-General's Department.


Plan Vigipirate

  • Yellow - to stress vigilance
  • Orange - to warn of terrorist action
  • Red - to warn of serious attempts
  • Crimson - to warn of major attempts

Ireland (Republic of)

International Terror Threat Level

  • Low: An attack is deemed unlikely.
  • Moderate: An attack is possible, but not likely.
  • Substantial: An attack is a strong possibility.
  • Severe: An attack is highly likely.
  • Critical: An attack is imminent or has occurred.

Administered by the Garda Síochána.[1]

Since November 2015, the international terrorism threat level is considered to be at moderate, meaning an attack is "possible but not likely".[2][3]



  • Blue - an unconfirmed information about real terroristic threat[4]
  • Yellow - a confirmed information about real terroristic threat
  • Red - an information about committed terrorist act

United Kingdom

  • Low - an attack is unlikely
  • Moderate - an attack is possible, but not likely
  • Substantial - an attack is a strong possibility
  • Severe - an attack is highly likely
  • Critical - an attack is expected imminently or has occurred

Administered by the Joint Terrorist Analysis Centre

United States

Wikinews has related news:
  • US government to replace color-coded terror alert system

Homeland Security Advisory System

  • Low - Low risk of terrorist attacks
  • Guarded - General risk of terrorist attacks
  • Elevated - Significant risk of terrorist attacks
  • High - High risk of terrorist attacks
  • Severe - Severe risk of terrorist attacks

Administered by the Department of Homeland Security

National Terrorism Advisory System

  • Elevated Threat - Significant or high risk of terrorist attacks
  • Imminent Threat - Critical risk of terrorist attacks


  1. ^ O'Keeffe, Cormac (2 May 2016). "What is the reality of the threat posed by Islamic extremists in Ireland?". Irish Examiner. Retrieved 11 May 2016.
  2. ^ "Terror threat level unaffected by attacks". Irish Independent. 27 June 2015. Retrieved 1 July 2015.
  3. ^ Williams, Paul; Brady, Tom (24 November 2015). "Units to counter terrorism step up training". Irish Independent. Retrieved 24 November 2015.
  4. ^ УРОВНИ ТЕРРОРИСТИЧЕСКОЙ ОПАСНОСТИ | Национальный антитеррористический комитет(in Russian)

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