Abstract: An environmental (weather) protective cover for a vent conduit. In accordance with some embodiments, a flexible body portion is adapted to cover a distal end of a vent conduit coupled to an upstream pressure source. A flap supported by the body portion has a flap slot opening. The body portion and the flap have a closed mode in which the vent conduit is sealed and an open mode in which the body portion and the flap slot opening are expanded when pressurized fluid discharging from the vent conduit is sufficient to flex the body portion and increase the slot opening to discharge the pressurized fluid. The body portion and the flap return to the closed mode when the pressurized fluid has been released.