Rhine Canyon

Almost 10'000 years ago, a huge rockslide occured near Flims in the Swiss Alps, in the Canton Grisons (German: Kanton Graubünden, Romansh: chantun Grischun). Some 12 km³ of rocks have been displaced. This was one of the largest rockslides ever, known to mankind.

Before the rockslide, the Rhine was flowing through a 1500m wide valley at an altitude of 600m. The rocks and the debris did fill up the valley and hinder the flow of the Rhine, which did build several lakes, the largest of them being the lake of Ilanz, at an altitude of 936m.

Filling up the lake of Ilanz did take several years. Later, the embankment of the lake did collapse and the level of the lake did drop to an altitude of 820m. but the lake didn't disappear entirely. This lake did exist for some 2000 years. Then the Rhine did carve a canyon into the debris. It is called the Rhine Canyon or the Swiss Grand Canyon, the Ruinaulta in Romansh (high boulder field).

The debris, coming down from an altitude of 2700m, did add some 750m height to the 600m altitude of the original valley. Today, the Rhine has already carved some 400m into the debris, thus building a canyon, but it has not yet reached the altitude of 600m where the river was flowing before the rockslide.

The boulder field being of no interest to the agriculture, the Ruinaulta remained a forested area until today. There are many trekking paths through the canyon and above, which allow tourists to admire the bumpy landscape. While there are very few accesses and parking possibilities for cars, the Rhaetian railway (German: Rhaetische Bahn, Romansh: Viafier Retica) goes through the canyon and serves many access points for trekkers. The Station Versam-Safien is a good access point to several trekking pathes.

There is an observation platform near Bonaduz, named Zault (built 2010) and another one on the opposite side near Conn, south of Flims (Romansh: Flem), named Il Spir (built 2006). Il Spir has the form of a swift hanging over the canyon.

At the eastern end of the Rhine Canyon, the Anterior Rhine (German: Vorderrhein, Romansh: Rain Anteriur) and the Posterior Rhine (German: Hinterrhein, Romansh: Rain Posteriur) meet together to form the Alpine Rhine (German: Alpenrhein). The confluence is located at Reichenau-Tamins (Romansh: Reichenau-Tumein). The Anterior Rhine is 4km longer than the Posterior Rhine, but the latter carries more water (60m³/s) than the former (54m³/s).