Emergence of the land then closed the channel through the Strait of Öresund. The lake rose until at about 11,200 BP it broke through a narrow corridor in the region of Mount Billingen in present-day south-west Sweden; Quaternary geologists used to describe the break-through as a massive, single tap of Niagara-like force, but it is now considered more likely that it happened in several steps over a limited period, perhaps a century, and along different local troughs and passages. By 10,800 BP the lake had dropped . At that point the climate reverted into cooling, and during a cold-climate period the glacier advanced again over the central Swedish exit. The lake became blocked again, rose about , and broke through the Strait of Oresund. By this time the Gulf of Finland had been deglaciated.