ROCHESTER, N.Y. – Arctic air has wide ranging impacts on the environment, and as the winter season progresses, the Great Lakes undergo one of their most noticeable transformations. Using satellite data, WHEC First Alert meteorologists can monitor ice coverage across the Great Lakes and compare it to seasonal averages. Currently, ice covers approximately 41 percent of the total surface area of the Great Lakes. Extensive ice coverage limits evaporation from the lake’s surface, effectively reducing the moisture supply needed for significant lake-effect snow. Heavy ice coverage can create challenges for commercial shipping and navigation across the Great Lakes.