Dear Tom,

Cities east of the Great Lakes can get very heavy snow, sometimes 24 inches or more, in one lake-effect snow event. What is Chicago’s largest lake-effect snow event?

Kevin Chicago

Dear Kevin,

Arctic air surges generally occur with strong northwest winds, so resulting lake-effect snows typically hit the eastern shores of the Great Lakes. Chicago does get some lake-effect snow when winds blow in from the northeast, but typically the area receives lake-enhanced snowstorm totals from the organized northeast winds that accompany snow-producing low-pressure systems passing south of the city. Chicago weather historian Frank Wachowski recalls that one of the area’s heaviest lake-effect snow events was on December 19, 1973, when 5.5 inches fell in the city, with snow amounts increasing to as much as 24 inches north of the city to Green Bay.