Norwegian bases changed the Arctic convoy problem

German bases in Norway brought submarines and aircraft within reach of the Arctic convoy route. Winter darkness offered convoys some cover, but the southward movement of sea ice forced shipping closer to the Norwegian coast and its airfields. Bergen, Narvik and Trondheim supported U-boat operations, with Hammerfest and Kirkenes providing further facilities. Holding Norway also helped Germany avoid the confinement it had faced during the First World War. Without access to both sides of the North Sea, German submarines would have faced a more restricted route through waters that Britain could more easily obstruct.