The term “all hell broke loose” means a situation suddenly descended into total chaos and confusion. It is a past tense sentence indicating the event happened in the near or distant past. Events tend to be relatively peaceful before something triggers the chaos. The phrase is idiomatic because the meaning cannot be garnered from a direct translation of its constituent words.
“All hell broke loose” is derived from both Christian and pre-Christian religions across Europe. Many pagan or polytheistic religions including Roman, Greek and Anglo-Nordic had places where there were bad people and monsters. Hell is directly related to the Anglo-Norse version of Hell and the Goddess, Hel, who ruled over it. The word is linguistically consistent over all Germanic languages from Frisian to Gothic.
The idea of hell breaking loose developed under Christianity, but had its origins in the Anglo-Nordic religion. Part of the mythology has Hell breaking open as part of Ragnarok, the apocalypse of the Gods and the reshaping of the world. Christianity added to the idea with demons and the Devil, but did not create it. In both mythologies, hell literally broke open and its contents poured onto Earth, causing chaos and destruction.
It is used as a term of recollection and most often appears when somebody is describing events. This can either be firsthand experience or secondhand reporting. “All hell broke loose” is usually preceded by ‘then’ to demonstrate a continuation of events in the narration.
Coup d’états often give rise to use of the term, too. It is used to indicate the breakdown of law and order within a society. It has been used, for example, in countries such as Iraq in 2003, in Thailand during political riots and in Libya in 2011. As one government falls, there is a vacuum until the new one asserts its power, and this allows chaos to develop as people take advantage.
Several television shows and documentaries have used “all hell broke loose” as a title. In 1995, Israeli director Amir Feldman produced a documentary about the lives of two victims of a suicide attack in his country. Television show “Charmed” also used it as an episode title. The second season of “Supernatural” concluded with a two-part episode with the same title where hell literally broke loose on Earth.