The gutter consists of a gutter base, gutter flap, and pneumatic actuator. The actuator is controlled by a gutter controller which senses rain and controls the actuator. In rainy weather, a rain sensor at the gutter controller senses rain and pumps air into the actuator to raise the gutter flap to form a V-shaped gutter. In dry weather, when most of the debris is collected in the traditional gutter, the air is drained from the actuator and the gutter flap lies flat, letting the debris slide down to the ground.