iceberg vs snowfall

iceberg

noun
  • A huge mass of ocean-floating ice which has broken off a glacier or ice shelf 

  • An aloof person. 

  • An impending disastrous event whose adverse effects are only beginning to show, in reference to one-tenth of the volume of an iceberg being visible above water. 

snowfall

noun
  • An instance of falling of snow. 

  • The amount of snow that falls on one occasion. 

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