calamity vs false alarm

calamity

noun
  • The distress that results from some disaster. 

  • An event resulting in great loss. 

false alarm

noun
  • A thing or occurrence which initially causes fear, distress, etc. but which is subsequently recognized as being no cause for concern. 

  • A warning signal (such as the call of sentry, the ringing of a bell, or the shriek of a siren) which turns out to have been given erroneously. 

How often have the words calamity and false alarm occurred in a corpus of books? (source: Google Ngram Viewer )