cataclysmic
adjective /ˌkætəˈklɪzmɪk/
/ˌkætəˈklɪzmɪk/
[usually before noun] (formal)- (of a natural event) causing sudden and violent change synonym catastrophic (1)
- a cataclysmic earthquake/flood/eruption
- extreme and very bad
- cataclysmic changes in society