Pre-breakdown currents in crystallographically oriented breakdown channels initiated from positive needle in alkali-halide monocrystals KCl and KBr subjected to pulses of voltage up to 140 kV with duration of 8 ns and rise time less than 0.5 ns were defined. Velocities of channel propagation have been also measured. A method of estimation of conductance of breakdown channel in ionic crystals is proposed and tested.