northwestern and central European climatic regions and thus is affected by the conjuncture of weather moving east from the British Isles and the Atlantic with that moving westward out of Russia. At Stavelot freezing weather averages 112 days a year, at Bastogne 145 days. The structure of the soil will permit tank movement when the ground is frozen, but turns readily to a clayey mire in time of rain. Snowfall often attains a depth of ten to twelve inches in a 24-hour period. Snow lingers for a long time in the Ardennes but-and this is important in recounting the events of 1944-the deep snows come late. 
 The best of numerous terrain descriptions of the Ardennes was prepared by the German General Staff in 1940, especially for the offensive in the west. It is entitled Militaergeographischer ueberblick ueber Belgien und angrenzende Gebiete. See also the British official publication of 1918: A Manual of Belgium and the Adjoining Territories (ed. The Admiralty). The best analysis of German military thought on the problem presented by the Ardennes terrain is in a manuscript by Magna E. Bauer entitled Comparison Between the Planning for the German Ardennes Offensive in 1944 and for the Campaign in the West in 1940 (1951). OCMH.