A blade for a rotor of a wind turbine has a substantially horizontal rotor shaft, the rotor including a hub, from which the blade extends substantially in a radial direction when mounted to the hub. The blade includes a profiled contour including a leading edge and a trailing edge as well as a pressure side and a suction side, the profiled contour when being impacted by an incident airflow generating a lift. The profiled contour is divided into a root region with a substantially circular profile closest to the hub, an airfoil region with a lift generating profile furthest away from the hub, and a transition region between the root region and the airfoil region. The profile of the transition region gradually changes in the radial direction from the circular profile of the root region to the lift generating profile of the airfoil region. The suction side comprises at least a first zone, which extends substantially in the direction of the incident airflow, and which is positioned in a zone of a cross-flow. The first zone includes a first barrier generating means adapted to generating a barrier of airflow, which extends essentially in the direction of the incident airflow, the barrier of airflow being of sufficient strength and length so as to effectively reduce the cross-flow.