There is a lack of hydrodynamic data under supercritical conditions, in particular in systems that attempt to isolate hydrodynamics from mass transfer. This paper presents hydrodynamic data focusing on the characterization of flooding. Two different flooding phenomena are identified using the column overheads, pressure drop and liquid hold-up of the system. It is further noted that the saturated fluid properties of density and dynamic viscosity play a significant role in flooding. A density difference of less than 250 kg/m3 between phases and a decrease in liquid viscosity causes a shift from classical gas-liquid flooding to behaviour more analogous to that of liquid-liquid extraction columns.