In the spring of 1917 it became clear that a new military offensive would soon be launched. An increasing number of soldiers were billeted in the BIE-region, and Allied bombardments on strategic targets in the area had been growing in frequency. In late July, the Allied forces launched a major offensive. Their intention was to advance from Ypres to the Flemish ports of Zeebrugge and Ostend. However, their ambitious plans fell through. For three long months, the Allies fought very hard, but around one hundred thousand casualties were suffered on both sides near Passchendaele. The municipalities that were closest to the front, such as Westrozebeke, Moorslede, Slijpskapelle and Dadizele, were now a stone’s throw from the front lines and were completely destroyed. The numerous hospitals were once again flooded with wounded soldiers and the German military cemeteries began to reach full capacity. 

On 31 July 1917, the British summer offensive erupted. It is known as the battle of Passchendaele, a battle that gained the Allies almost no ground but cost the lives of many soldiers. During the battle, troops moved position frequently. Hundreds of wounded soldiers were transferred to a safer location behind the front. The church of St-Josef on the Geite in Hooglede, for instance, served as an important first aid station in the summer of 1917. The newly constructed cemeteries in Hooglede received a great number of fallen soldiers every day.

In the meantime, the war front gradually moved in the direction of Staden. Due to their favorable location on the Stadenberg, the Germans were able to stand their ground. Staden was completely destroyed as a result of the relentless fighting in the area. Westrozebeke, too, was reduced to rubble in the summer of 1917. 

The shifting of the war front came to a stop near Moorslede. Three months of constant shootouts had transformed the terrain in the area to a moonscape. The church of Moorslede, among others, was a popular target for British artillery fire during the offensive. In order to put a stop to the attacks on the church, the Germans decided to detonate it themselves in July 1917. The basilica in Dadizele was bombed by the Allies. 

The Third Battle of Ypres came to an end in early November, but the region remained unstable for a while after that as the air strikes and artillery bombardments kept up. Municipalities such as Ingelmunster, Roeselare and Izegem were taken under fire with increasing frequency. For this reason, some municipalities were partially or completely evacuated, although the local population did not always take the instructions to heart.