inferno vs smouldering

inferno

noun
  • A large fire; a conflagration. 

  • A place or situation resembling Hell. 

smouldering

noun
  • The act by which something smoulders; residual heat. 

adj
  • Burning slowly, producing smoke but no flame. 

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