We investigate the propagation of a thin flame that passes transversely through a periodic array of stretched vortices. The effect of different rates of stretching and different strengths of vortices on flames with various flame speeds is calculated by the use of ray-tracing equations. The results show that the presence of stretched vortices enhances the propagation of flames except in flows with very strong mixing where there can be an adverse effect on the mean speed of the flames through the vortices. Ultimately this can result in it being impossible for dames to propogate at all past the vortices; instead they would reside solely within the cores of the vortices.