If the Great Lakes completely froze over, would that stop the lake-effect snow machine?
— Chris Wells, Vernon Hills
It would indeed. A frozen lake would act as nothing more than snow-and-ice-covered ground and would effectively cut off the formation of any lake-effect snow. Lake-effect snow develops when moisture from the open lake water is evaporated into the cold air mass passing over it and cooled to condensation, forming clouds and snow. This evaporation would cease if the lake were frozen. Most of the Great Lakes do not freeze except in the severest of winters, but Lake Erie, the shallowest of the Great Lakes, (less than 100 feet deep in many areas) usually becomes more than 80 percent covered in ice, drastically reducing the amount of lake-effect snow in late winter for cities such as Buffalo, Erie and Cleveland.