Many of the Southern pickets were driven to shelter.

While the whole Southern army sought protection from the deluge, the Army of the Potomac, still a hundred thousand strong, and carrying all its guns, marched in perfect order over the six bridges it had built, breaking the bridges down behind it, and camping in safety on the other side.

The river was rising fast under the tremendous rain, and the Southern army could find no fords, even though it marched far up the stream.
Fredericksburg was won, but the two armies, resolute and defiant, gathered themselves anew for other battles as great or greater..