"Lake-effect" snows are visible in this true-color Moderate Resolution Imaging Spectroradiometer (MODIS) image from December 10, 2002. Cold air from the Arctic passes over the warmer waters of the Great Lakes and picks up evaporated moisture. The cold air chills the moisture, which then falls as snow on the downwind side of the lakes. Since the air flow across the Great Lakes region of North America is generally somewhere between east and south, the heaviest lake-effect snows are experienced south and east of the Lakes. The Great Lakes are (left to right) Superior, Michigan, Huron, Erie, and Ontario.