squall vs willy willy

squall

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

  • A loud cry or wail. 

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

verb
  • To cry or wail loudly. 

willy willy

noun
  • A whirlwind, cyclone or tornado; a dust devil. 

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