Defcon Levels History & List Of Alert Level ChangesHistory of official changes to the defcon level since the United States started using the defcon warning system. At times the official defcon alert level isn't released to the public until later for security reasons.
September 11th, 2001: Attacks On The Twin TowersOn September 11th, 2001 after four hijacked planes flew into the twin world trade center towers, one into the Pentagon and the fourth intended for Washington D.C. crashed into a field in Pennsylvania the Secretary of Defense issued an order to raise the defcon level to 3 with a possibility of raising it further, to 2.
Janury 15th, 1991: Gulf WarJanuary 15th, 1991 Defcon 2 was reached in the initialization phase of the Gulf war.
August 18th, 1976: Operation Paul Bunyan: Defcon Level 3On August 18th, 1976 the defcon alert level for United States forces stationed in South Korea were raised to defcon 3 throughout the duration of operation Paul Bunyan after two U.S. Military officers were killed by North Korean forces.
October 6th, 1973: Yom Kippur War: Defcon Level 3On October 6th, 1973 during the Yom Kippur war after Syria and Egypt launched an attack on Israel the Strategic Air Command, European Command, Sixth Fleet and US Military were all raised to defcon alert level 3 for a few days time after receiving reports that Russia had a ship on its way to Egypt carrying nuclear warheads.
October 22nd, 1962: Cuban Missile CrisisOctober 22nd, 1962 during the Cuban missile crisis the United States Armed forces were raised to defcon level 3 and the Strategic Air Command were raised to Defcon Level 2 until the 15th of November, 1962.