CLEVELAND - Waves from Lake Erie crash onto Cleveland Harbor West Pierhead Lighthouse as the subzero air temperature causes the water to freeze in multiple layers, coating the entire structure in ice and making it virtually impossible for mariners to see the light Dec. 14, 2010. Coast Guard units throughout the Great Lakes issued warnings to mariners that the ice may reduce or completely obscure the Cleveland lighthouse as well as other aids to navigation across the lakes. (U.S. Coast Guard photo by Petty Officer 2nd Class Lauren Jorgensen)