The Illgraben valley is one of the most geologically unstable regions of Switzerland, and is located south of Leuk in the Canton of Valais.

The Swiss Federal Institute for Forest, Snow and Landscape Research uses radars, microphones and cameras to register mudflow events, and to warn the population of Leuk.

[1] Several times a year, the Illgraben's mud flows cause the Rhône river to turn murky until it reaches Lake Geneva, which is 90 kilometers (56 miles) downriver.

From there, there is an unmarked trail to the Steinschlaghütte (English: rock fall hut), or to the alpine lake Illsee and the Illhorn.

[citation needed] Video documents by the Swiss Federal Institute for Forest, Snow and Landscape Research: