A fuel cell stack that includes a stack of fuel cells each having a cathode side bipolar plate including parallel cathode gas flow channels. Airflow from a cathode inlet manifold is directed to the flow channels to provide the cathode gas to the fuel cell membrane. The fuel cell stack includes a device positioned within the inlet manifold that selectively blocks a predetermined number of the flow channels for each cell at low load operation to increase the flow rate in the unblocked flow channels, so that the fuel cell stack generates the desired low load output, and the increased flow rate prevents water from accumulating in the unblocked flow channels.