プログレッシブ和英中辞典(第4版)の解説
いへん【異変】
〔事故〕an accident；〔異常なこと〕something unusual
父の身辺に異変が起きたのではないかと心配した
I was afraid that 「something had happened to [《文》 some accident had befallen] my father.
一大異変が生じた
An extraordinary event took place.
去年は天候異変の年だった
We had unusual weather (all) last year.