ISS015-E-05624 (29 April 2007) --- The Niagara River, eastern end of Lake Erie and western end of Lake Ontario are featured in this image photographed by an Expedition 15 crewmember on the International Space Station. In contrast, an image photographed by an Expedition 14 crewmember just a month earlier on March 21, 2007 (ISS014-E-17999) shows Lake Erie clogged with ice that is pushed against the shore line by the prevailing weather systems from the west. These two images document the breakup of the Lake Erie ice pack, the unofficial signature of spring for residents of Buffalo and Niagara Falls. During the winter months, the ice collects in Lake Erie and is prevented from flowing down the Niagara River (the international boundary between Ontario, Canada and New York State) by the Lake Erie-Niagara River Ice Boom. The 2,680-meter (8,800-foot) boom, administered by the 1909 Boundary Water Treaty's International Niagara Board of Control, is deployed each December. Operational since 1964, the boom serves several functions: it protects the water intakes for the Niagara River power plants, and minimizes ice runs and ice blockages that can create damage and flooding along the river. At the height of winter, the thickness of the ice at the Buffalo harbor can reach 3.5 meters (12 feet). The removal of the ice boom, usually in early April, is now marked by local celebrations. This year the boom was removed in mid-April, a bit later than usual.