The flow fields of wake-stabilized jet flames in a transverse air stream have been studied experimentally employing reactive Mie scattering flow visualization and laser Doppler velocimetry. Five characteristic flow modes are identified in different ranges of jet-to-wind momentum flux ratio, R: down-wash (R < 0.1), cross-flow dominated (0.1 < R < 1.6), transitional (1.6 < R < 3.0), jet dominated (3.0 < R < 10), and strong jet (R > 10) modes. The streamlines, vorticity distributions, as well as flame appearance, which vary significantly in the different modes, are presented and discussed. The down-wash and reverse flow regions are recognized as the primary mechanisms related to the flame stability. The reduction of the down-wash effect with increase of the jet-to-wind momentum flux ratio and the change of vorticity from negative to positive in the near-wake region of the burner tip lead to blow-off of flames. The turbulence intensity in the wake of the jet is stronger than that in the wake of the tube. The values of Reynolds shear stress at the plane of symmetry are positive in the wake of the jet, but negative in the wake of the tube.