The Blizzard of 1966 was a nor'easter that impacted the northeastern United States and Eastern Canada from January 29-February 1, 1966. Heavy lake effect snows preceded the cyclonic storm southeast of Lake Ontario. In and around the Lake Ontario snow belt, the storm period is considered to have lasted from January 27 - February 1, 1966, and the blizzard was a combination nor' easter and lake effect event in this region.

A blizzard is a severe snowstorm characterized by strong sustained winds and low visibility, lasting for a prolonged period of time—typically at least three or four hours. A ground blizzard is a weather condition where snow is not falling but loose snow on the ground is lifted and blown by strong winds. Blizzards can have an immense size and usually stretch to hundreds or thousands of kilometres.