Following the initial momentum gained from the element of surprise that the Germans enjoyed during the opening phases of the Battle of the Bulge, their attack petered out as supplies of troops and equipment dwindled. The severe winter weather had proved a blessing and a hindrance to both sides, generally serving to block roads when high numbers of German tanks were involved in offensive operations. When the ground hardened amidst cold spells once the German offensive was well underway, the Allies regained their important air superiority. Additionally, the Germans were suffering from a severe shortage of fuel due to the effectiveness of ongoing Allied bombing campaigns against German fuel infrastructure. Coupled with the constant reinforcements of Allied troops from the west, the tide of battle had swung considerably against the Germans by January whilst Allied offensives on either side of the Bulge cut off many Germans before they could retreat.
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