Since August 6, 1861, thousands of Confederates had been camped in the area around Major General Sterling Price's headquarters while waiting to attack the Union Army in Springfield. On the night of August 9, the expected orders were issued, pickets were called in, and the army began to advance, but rain led the Confederates to postpone the attack because they feared their black gunpowder would become wet. The army returned to camp, but the pickets were not ordered back to their posts, leaving the Confederates without warning of a Union advance. On the morning of August 10, Confederate officers at Price's headquarters did not know that Union columns were approaching their camps from two directions, and shortly after dawn the Federals launched a surprise attack.