In November, with the southwest winds still raging, the farm's construction had already ground to a halt when the cement could no longer be mixed. Then came a night when the gale struck with such violence that the farm buildings rocked on their foundations and tiles were torn from the barn roof. The hens, waking in terror, claimed they had all dreamed simultaneously of a distant gunshot. By morning, the flagstaff lay flattened, and an elm tree at the foot of the orchard had been ripped from the earth like a radish. But the animals had barely registered these signs when a cry of despair broke from every throat: the windmill, the great project that had absorbed nearly a year of their labor, lay in ruins. The stones they had broken and hauled with such devotion were scattered across the ground, and the walls they had raised foot by foot were now a heap of rubble.

The animals dashed to the knoll where the windmill had stood. Napoleon, who seldom moved faster than a walk, raced ahead of them all. He stood before the leveled structure, his tail rigid and twitching, and paced in silence, snuffing at the ground. Then, as though his mind were made up, he halted and addressed the assembled animals. In a quiet voice he asked who was responsible, and then roared the name "Snowball!" He declared that the expelled pig had crept in during the night, out of sheer malignity, to destroy the work of nearly a year. He pronounced a death sentence on Snowball, offered the title "Animal Hero, Second Class" and half a bushel of apples to any animal who brought him to justice, and a full bushel to anyone who captured him alive.

The windmill had been a point of bitter contention between Snowball and Napoleon since its proposal. Napoleon had argued that the great need was to increase food production, while Snowball maintained that the windmill would save labor and allow a three-day week. The animals were divided, and the debates were conducted during the Sunday meetings, where the pigs put forward resolutions and the animals voted. The destruction of the windmill thus struck at the heart of the farm's most divisive issue, and Napoleon's accusation of Snowball gave the animals a target for their grief and anger, even as the rubble still lay where it had fallen.