Snow ice forms a significant fraction of the thickness of Antarctic sea ice, particularly in the Bellingshausen/Amundsen Sea sector where snow accumulation rates are high and dominate the ice mass balance. Brine exchange processes during flooding and refreezing impact ice mass balance, ice properties and biological communities, yet are poorly understood. We investigate the impact of the physical representation of brine exchange during the flooding and consolidation of a slushy layer with a one-dimensional fluid dynamic–thermodynamic sea-ice model. The sensitivity of snow-ice formation and ice thickness to brine exchange parameterization is examined for three cases: (1) little or no convection with purely diffusive heat transport; (2) vigorous convection with a Stefan freezing condition; and (3) convection governed by a Rayleigh number parameterization. The impacts of the representation of fluid transport during flooding are also examined. Results are compared with temperature data obtained from ice mass-balance buoys deployed in winter 2001 and 2002 in the eastern Bellingshausen Sea and in 2007 in the western Bellingshausen Sea. Consistent with previous observations, brine convection appears to play an important role in the thermal and salinity evolution of sea ice in the Bellingshausen Sea. By comparison of model results with observations, we place bounds on the importance of the thermodynamic treatment of flooding on ice mass balance. The implications for representing snow-ice formation in large-scale models are discussed.