On August 26th, 1951, after heavy rainfall and thunderstorms, a mudflow was triggered in the so called Jagawoferl-creek. Most of the rock masses were deposited in the forest, water and mud masses tumbled down to the lake. A similar event occurred in 1975 when temporary protective structures from 1968/69 were partially destroyed.
In 1987 rows of log fences and dams made of logs and debris material were built so that the debris and mud load would deposit as completely as possible in the forest area during such events.
