Flims rockslide
The Flims rockslide happened about 10,000 years ago (8000 BC) in eastern Switzerland. It is the biggest known landslide incident in the Alps, and the biggest worldwide whose effects are still visible, moving some of rock, about 300 times that of the historic Swiss Goldau landslide. The town of Flims can be found at the line where the slip surface disappears under the debris. North of Flims the rock face of "Flimserstein" stands high whereas more westerly the slide surface is clearly visible. South of Flims is a huge hilly debris area that has been forest ever since , as this area is not suitable for farming, firstly for its shape and, even more for its lack of water. The river Rhine crosses this debris in a gorge called Ruinaulta. The Rhine still runs in debris, which shows that it has not yet reached its level as before the incident. The highest hill in the debris area is almost higher than Flims at the end of the sliding surface. Landscape. The top of the slide surface can be found at above sea north of Flims at Fil de Cassons; the end of the slide surface is at about 1100 . The pre-slide valley would have been at . The rock is Mesozoic limestone, including Mergel; the angle of slide is (only) 20° to 25°. Debris covers . Pressure baked the debris together to a somewhat stable rock. Given the river Rhine as a base of the valley, the debris is as high as . This debris dammed the Vorderrhein and created a lake in the Ilanz area. The level of the lake was found to have been at a maximum of above sea level, which results in a lake some long. Dating. Clemens Augenstein from "Geologisches Institut der ETH Zürich