The Eurasian Weichselian glaciation was studied with the SICOPOLIS (Simulation Code for POLythermal Ice Sheets) ice-sheet model. The forming ice sheets are very sensitive and respond quickly to changes in temperature and precipation. This indicates a great sensitivity to the climatic signal, especially in the Fennoscandian sector of the ice sheet. The simulation results suggest areal and temporal variations in fast-flow areas. The fast flow areas that form are located in topographic troughs.