Sand (yellow) between peat (black) and man-made detritus (green) is proof of an ancient tsunami. | Graphic: V. Nigg et al. (2021)

Some 1,300 years ago, earth masses slid into the Silser Lake and triggered a tsunami that caused a flood wave up to three metres high that swept over the plains of the Upper Engadine. The evidence of this lies in drill core analyses and models made by geologists at the University of Bern. Their findings also explain the deposit of a sandy sediment layer (yellow) between peat (black) and man-made detritus (green); earlier investigations into the last of these layers have revealed stone altars from the time when the land was occupied by the Romans.

V. Nigg et al.: A tsunamigenic delta collapse and its associated tsunami deposits in and around Lake Sils, Switzerland. Natural Hazards (2021)