Operation Avalanche Operation Avalanche Operation Avalanche was the codename for the Allied landings near the port of Salerno, executed on 9 September 1943, part of the Allied invasion of Italy. The Italians withdrew from the war the day before the invasion, but the Allies landed in an area defended by German troops. Planned under the name "Top Hat", it was supported by the deception plan Operation Boardman. The landings were carried out by the US Fifth Army, under American General Mark W. Clark. It comprised the U.S. VI Corps, the British X Corps and the US 82nd Airborne Division, a total of
Operation Avalanche the Allied armies a grinding and attritional slog against skillful, determined and well prepared defenses in terrain and weather conditions which favoured defense and hampered the Allied advantages in mechanised equipment and air superiority. It took until mid-January 1944 to fight through the Volturno, Barbara and Bernhardt lines to reach the Gustav Line, the backbone of the Winter Line defenses, setting the scene for the four Battles of Monte Cassino which took place between January and May 1944. Operation Avalanche Operation Avalanche was the codename for the Allied landings near the port of Salerno, executed on 9 September 1943, part