We present the results of the analysis of large two-ribbon solar flare H_α-images, spectra as well as of X-ray and radio emissions for the most energy release period. We study variations of the chromospheric motion line-of-sight velocities during the flare in its different kernels. They are compared with the variations of the hard X-ray and microwave emission at a wavelength of 6 cm. Some chromospheric downflows are revealed in the flare kernels before and at the maxima of the hard X-ray emission.