The long-term evolution of loess accumulation on a hill located in the Belgian loess belt is investigated via field observations and wind tunnel simulations. Analysis of the modern field pattern reveals that the present hill is the result of a rather complex evolution where two distinct hills were united by progressive loess accumulation. Due to a strong asymmetric loess accumulation, with much more accumulation on the upwind slopes, the hill migrated a considerable distance in the upwind direction. The temporal and spatial evolution of the field loess accumulation was simulated on a topographic scale model in the wind tunnel. Results indicate that such simulations are an important aid in understanding the long-term accumulation of loess. Simulating the complete original loess deposit in a single wind tunnel experiment is only possible, however, if syngenetic erosion and colluviation processes can be incorporated in the wind tunnel simulation.