The planned attack slipped from 4 April to 6 April after heavy rain slowed Johnston's army. The 23-mile march took three days after 48 hours of rain. Union and Confederate scouts skirmished, prisoners were taken, and the advancing Confederates made enough noise that Beauregard doubted surprise remained. Rations were also running short, making any prolonged engagement increasingly dangerous. Johnston nevertheless pressed on because delay allowed Grant and Buell to unite.
Notable Point · 1:30:48-1:33:21
Rain, delay, and the limits of Confederate surprise
Rain turned a short Confederate march into a three-day movement, bringing the attack closer to Buell's arrival and eroding the surprise it needed.