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What is a cirque lake and where does it come from?

 

At 910 meters above sea level, lake Wildsee is located in the southern part of the Black Forest National Park, not far from the Seekopf mountain, which rises 1,055 meters. The Wildsee is about eleven meters deep. It is surrounded by a forest area that was already declared a ban forest in 1911, which means that it has not been cultivated since then and is completely left to itself. The cirque wall behind the Wildsee is 125 meters high. Its water drains off via the Schönmünz stream, which in turn flows into the Murg.

 

The Wildsee is a glacial cirque lake, as they are often found in the highlands of the Black Forest. Cirque lakes were formed by glaciers that created depressions on mountain slopes. The ice of the glaciers slowly sinks downhill. Underneath, debris and rock is detached from the ground and carried along. This permanent pushing causes the underlying soil to deepen into a depression. This is the basin of the later cirque lake, which fills as the glacier gradually melts. It is interesting to note that cirques in the Black Forest formed mainly on northern to eastern slopes. This is due to the fact that more snow had accumulated there and thus the amount of ice carried downhill by the glacier was greater.

 

The cirque lakes formed during the last ice age, when the Black Forest was glaciated. Other well-known bodies of water of this type are Feldsee (near Feldberg), Mummelsee (near Seebach in the Ortenau district) or Nonnenmattweiher (Kleines Wiesental). Typical for all of them is their shape with a relatively flat, deepened bottom and a mostly steep back wall. Cirque lakes do not only occur in the Black Forest, but in principle everywhere where there were glaciers before.