出典:Wikipedia
出典:『Wikipedia』 (2011/06/11 14:34 UTC 版)
The Soo Locks allow ships to travel between Lake Superior and the lower Great Lakes. The locks pass an average of 10,000 ships per year. This is achieved in spite of the locks being closed during the winter from January through March, when ice shuts down shipping on the Great Lakes. The winter closure period is used to inspect and maintain the locks.