Efforts to validate aerodynamic models of vertical-axis wind turbines have been limited by a lack of appropriate measurements as stall begins to occur along the blade. In order to measure the forces acting on a blade through stall and in post-stall, a blade has been instrumented using flush-mounted pressure transducers. Data have been obtained on an appropriate range of turbine operating conditions. These data indicate that at high incident wind speeds, dynamic stall occurs on the upwind portion of the rotation.