From a practical perspective, Dragon Break is Bethesda's
Deus Ex Machina (no not the video game
). It's a plot device that's used to resolve a seemingly unsolvable problem with a usually abrupt, unnatural and unexpected event, character, object, or power. In the game
Elder Scrolls II: Daggerfall, the consequences of the player's choice regarding who gets the Totem that controls bronze colossus Numidium are markedly different from another. Bethesda needed a way to resolve all the contradictory endings so it created the Dragon Break, a warping of reality where time temporarily becomes non-linear (the term Dragon Break comes from Akatosh being the Dragon God of Time) enabling otherwise contradictory outcomes to co-exist and then resolve as something completely different than what they were before the Dragon Break once it ends. That particular Dragon Break was known as The Warp In The West and with it Bethesda was able to create a completely different outcome from the events of Daggerfall. To obscure it as a plot device, Bethesda then also sprinkled the history of Tamriel with other Dragon Breaks. The Dragon Break described in
Where Were You When the Dragon Broke? is one of the other Dragon Breaks which occurred when Tiber Septim first activated Numidium in Elsweyr.