The column had to move slowly enough to be controlled but quickly enough that the camp below did not have long to organize a defense.

The camp was warned — the Comanche leader Red Warbonnet is credited in some accounts with discovering the soldiers and alerting the camp before the descent was complete.

But the warning came too late for organized military resistance.

The warning was in time for the families to flee.

The geography of the canyon — the steep walls, the narrow entry points, the length of the canyon system — that had made it an attractive refuge had a specific tactical consequence: once soldiers began descending on the only available path, there was nowhere else to go except down the canyon and away from the soldiers.

The geography that had sheltered the camp became the geography that channeled the retreat.