The Northwest Passage consists of a series of very deep channels that wind through Canada's Arctic Islands. The Northwest Passage is about 900 miles (1450 km) long. Using the passage instead of the Panama Canal can cut thousands of miles off of a sea journey between Europe and Asia.Unfortunately, the Northwest Passage is about 500 miles (800 km) north of the Arctic Circle and is covered by ice sheets and icebergs much of the time.Some speculate, however, that if global warming continues the Northwest Passage might be a viable transportation route for ships.he Northwest Passage is about 900 miles (1450 km) long. Using the passage instead of the Panama Canal can cut thousands of miles off of a sea journey between Europe and Asia.