Cataclysm means upheaval or disaster caused by sudden, violent change.
Cataclysm is a noun.
Synonyms: calamity, catastrophe, debacle, violent change, devastation.
Antonyms: success, triumph, victory.
The reports about the cataclysm came from the earthquake's that occurred in Haiti.
The revolution was a cataclysm that changed the entire political structure of the country.