A storm like that is an 'anomaly' for this area. [=a storm like that does not usually happen in this area]
The doctor detected an 'anomaly' [='irregularity'] in my heartbeat.
(..) If you explain to me the rules of the game, I might have even more fun. That's not a game. No, on the contrary. We play a game of errors, omissions, anomalies. For example Madrier. You almost warned me and thus saved my life. But you forgot to tell me why the SRPJ department was closed. (..)1981 To Kill a Cop