squall vs waul

squall

verb
  • To cry or wail loudly. 

noun
  • A loud cry or wail. 

  • A sudden storm, as found in a squall line. 

  • A squall line, multicell line, or part of a squall line. 

waul

verb
  • To wail, to cry plaintively. 

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