mishap vs natural disaster

mishap

noun
  • Evil accident; ill luck; misfortune; mischance. 

  • An accident, mistake, or problem. 

natural disaster

noun
  • The emergency situation that is the consequence of such an event. 

  • Any natural phenomenon that causes great damage and loss of life. 

How often have the words mishap and natural disaster occurred in a corpus of books? (source: Google Ngram Viewer )