flood tide vs undertow

flood tide

noun
  • The period between low tide and the next high tide in which the sea is rising. 

  • The highest point of something; a climax. 

undertow

noun
  • A short-range flow of water returning seaward from the waves breaking on the shore. 

  • A feeling that runs contrary to one's normal one. 

verb
  • To pull down by, or as by, an undertow. 

  • To flow or behave as an undertow. 

  • To pull or tow under; drag beneath; pull down. 

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