 Deglaciation following the Weichselian glaciation took place in the Lake Ladoga basin between 12,500 and 11,500 radiocarbon years BP.Lake Ladoga was initially part of the Baltic Ice Lake (70–80 m. above present sea level), a historical freshwater stage of Baltic Sea.It is possible, though not certain, that Ladoga was isolated from it during regression of the subsequent Yoldia Sea brackish stage (10,200–9,500 BP).