CLEVELAND - Ice completely covers Cleveland Harbor Main Entrance Light 1, a lighted green aid to navigation, and coats the piling of Light 4, a lighted red aid to navigation, Dec. 14, 2010, following a storm that brought heavy snow, high winds and subzero temperatures. Coast Guard units throughout the Great Lakes issued warnings to mariners that the ice may reduce or completely obscure aids to navigation. (U.S. Coast Guard photo by Petty Officer 2nd Class Lauren Jorgensen)