The supersonic air flow at Mach numbers of 1.1–1.6 in a shock tube is experimentally investigated during initiation of nanosecond pulse surface sliding discharges. The shadow images of the flow field after discharge initiation, which characterize the dynamics of shock waves propagating from the discharge area, are obtained. Periodic pressure pulsations on the shock tube channel wall are recorded. The pressure dynamics is shown to correspond to both the motion of shock waves from the discharge area and a supersonic flow of the discharge-excited gas near the channel wall. The pressure increase on the shock tube channel wall was 6–18%, as compared to the pressure in an unperturbed flow.