31 July 1917
The Battle of Passchendaele Opens

The dispiriting losses to the French in their part of the Allied offensive of April 1917 had led to widespread mutinies during the summer. As a result, the burden of continuing the attack on the Germans in the fall of 1917 fell to the British forces. Sir Douglas Haig, the British commander-in-chief, chose the Ypres salient as the site for his new offensive. He believed this area offered the greatest scope for a breakthrough, and the Royal Navy supported him, hoping that the army could capture the ports on the Belgian coast that the Germans were using as bases for their submarine offensive against Britain's seaborne trade.

The offensive began on 31 July 1917, but made disappointingly small gains. The British artillery bombardment, which was needed to shatter the enemy's defensive trench system, also wrecked the low-lying region's drainage system, and unusually rainy weather turned the ground into a wasteland of mud and water-filled craters. For three months, British troops suffered heavy casualties for limited gains.

On 16 August the attack was resumed, to little effect. Stalemate reigned for another month until an improvement in the weather prompted another attack on 20 September. The Battle of Menin Road Ridge, along with the Battle of Polygon Wood fought by the Australians on 26 September and the Battle of Broodseinde on 4 October, established British possession of the ridge east of Ypres.

In October, the Canadian Corps, now commanded by Lieutenant General Sir Arthur Currie, took its place in the front lines. On 26 October the 3^rd and 4^th Divisions launched the first Canadian assault, in rain that made the mud worse than ever. Three days of fighting resulted in over 2,500 casualties, for a gain of only a thousand or so yards (1 km). A second attack went in on 30 October. In a single day, there were another 2,300 casualties — and only another thousand yards (1 km) gained. On 6 November, the 1^st and 2^nd Divisions launched a third attack that captured the village of Passchendaele, despite some troops having to advance through waist-deep water. A final assault on 10 November secured the rest of the high ground overlooking Ypres and held it despite heavy German shelling. This marked the end of the Passchendaele offensive.

Sources: Imperial War Museum, Library and Archives of Canada and BBC Website