In recent earth history, the alternation of warm and cold periods during the Pleistocene has characterized the appearance of the Wiesental. The valley of the Schwarzwaldwiese was formed by the Feldberg Glacier. Only in the upper part between Fahl and Todtnau was the glacier powerful enough to carve out a trough valley into the crystalline basement. The glacial tongue, however, reached as far as Wembach. In the upper reaches, near Todtnau and Gschwend, the Wiese flows in some places through gorge-like valleys with rapids and small waterfalls.