Little Ice Forming on Great Lakes This Winter As Temperatures Stay Unusually Warm

The amount of ice that forms on the surfaces of Lake Superior, Lake Michigan, Lake Huron, Lake Erie and Lake Ontario each winter has major implications for Great Lakes ecology, weather, and shipping industries.

Thinner ice allows more evaporation and heat transfer into the air, affecting regional weather patterns. Reduced ice cover also leaves shorelines and fish eggs more exposed, while opening up the lakes for longer shipping seasons.

Ice typically reaches its maximum coverage from mid-February through early March. In an average winter, around 40% of the Great Lakes surface freezes over at peak icing. Last year, total ice cover topped out at only 23% in February and had declined to just 7% by mid-month.

The lack of extensive ice cover impacts the ecology of the Great Lakes in several ways. Less ice means more evaporation and heat loss during the winter, which can lower water levels in the lakes. It also allows more sunlight to penetrate the water, causing earlier warming that can affect aquatic ecosystems.

Exposed shorelines and fish eggs are more vulnerable without insulating ice cover. Eggs laid in the fall require ice shelter through hatching in spring. Declining ice threatens reproductive success for important species like lake whitefish.