What causes lake effect snow?
Lake effect snow is caused when cool winter air masses travel over warm waters of a large lake.
This usually occurs when large amounts of evaporation occur to form convective clouds that causes precipitation in the form of snow. Lake effect snow is very common in the Great Lakes region (especially upstate New York). Lake effect snow is more common during the early winters since the water has not have much time to cool. If a lake cools and freezes, lake effect snow is nearly impossible since convective clouds need warmer waters for evaporation to occur.