An apparatus for contouring particulate material may include a frame and at least one drum rotatably mounted on the frame such that the drum rotates substantially freely with respect to the frame about a central longitudinal axis. The drum may have opposite inboard and outboard ends and an outer surface therebetween. At least one blade may extend about the drum and protrude outwardly from the outer surface of the drum, and the blade may have an outer edge with a radius measured from the central longitudinal axis in a plane oriented in perpendicular to the central longitudinal axis of the drum to the outer edge. The outer edge of the blade may have a helical shape and the radius of the outer edge may be less at the outboard end of the drum than the radius of the outer edge at the inboard end of the drum.