We extend an earlier work on traveling waves in premixed
ames in a gravitationally stratified medium, subject to the Boussinesq approximation. For three-dimensional
channels not aligned with the gravity direction, and under the Dirichlet boundary conditions in the
fluid velocity, it is shown that a non-planar traveling wave, corresponding to a non-zero reaction, exists, under an explicit condition relating the geometry of the crossection of the channel to the magnitude of the Prandtl and Rayleigh numbers, or when the advection term in the
flow equations is neglected.