On December 16, 1944, German forces began their Ardennes Offensive, which led the the Battle of the Bulge. It would be the largest land battle for the US Army in the Second World War.
On that date, the 371st was still based at Dole, and flying combat from there, though the process had begun to shift operations to the new field at Tantonville (Y-1). As the group was still assigned to the 1st Tactical Air Force (Provisional) it supported the Sixth Army Group, with the Seventh Army, in the Alsace-Lorraine region of France. Other missions were flown into German territory opposite the region to interdict railroad and road traffic.
On the 16th the group flew three close support and two armed recce missions with good results. More missions could have been flown, but the group had to keep one squadron on standby for an escort mission that was later cancelled.
Rumors about the German breakthrough in the Ardennes abounded in the following days. They were in Liege, Belgium, or they had reached France. It was an anxious time for many as the group continued air operations and prepared to complete its move north to Tantonville.