Alsace is at the heart of the Rhine ditch. It is a plain 21 miles wide (35 km), bordered by the Black Forest to the east and the Vosges to the west. These two mountain ranges form an immense corridor. It is subject to an oceanic influence, but in a radically different way from north to south. There are three types of climate in Alsace. The first, known as mountainous, affects the inhabitants of the periphery of the Vosges. A second, softer, is found in the hunchbacked Alsace region. The last, which can be described as dry, extends on the plain.