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.
Australia 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.
France
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.
Since November 2015, the international terrorism threat level is considered to be at moderate, meaning an attack is "possible but not likely".
Netherlands
Russia Blue - an unconfirmed information about real terroristic threatУРОВНИ ТЕРРОРИСТИЧЕСКОЙ ОПАСНОСТИ | Национальный антитеррористический комитет 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
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
References