hurricane vs squall line

hurricane

noun
  • A wind scale for quite strong wind, stronger than a storm 

  • A severe tropical cyclone in the North Atlantic Ocean, Caribbean Sea, Gulf of Mexico, or in the eastern North Pacific off the west coast of Mexico, with winds of 119 km/h (74 miles per hour) or greater accompanied by rain, lightning, and thunder that sometimes moves into temperate latitudes. 

  • "full—triple-full—full" – an acrobatic maneuver consisting of three flips and five twists, with one twist on the first flip, three twists on the second flip, one twist on the third flip 

squall line

noun
  • A line of thunderstorms, hundreds of miles long, with squalls at the advancing edge. 

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