5 June 2017

Another video of the terrifying Illgraben debris flow in Switzerland

Posted by Dave Petley

Another video of the terrifying Illgraben debris flow

Last week I posted a number of Youtube videos of the terrifying Illgraben debris flow from Switzerland, which occurred on 29th May.  Pierre Zufferey has posted to Youtube a video that, if anything, is even better, of this enormous event:-


He has provided some accompanying text (in French), a part of which states (as translated by Google):-

What you can not feel through the video are: trembling under your feet; Vibrations, which even make the air enter the lungs; The smell, a smell of mud a little sulphurous, an odour that spreads in the valley of the Rhone for one or two days; It is the feeling of being very small … there is a kind of comparative relationship that settles where I grew ever smaller and the natural strength ever more enormous. Even after a week a kind of internal shock is still present and you feel the desire to kneel before Him who created everything, God.

The video captures the extraordinary violence and power of such an event, with its boulder-choked front and more fluid main body:-

terrifying Illgraben debris flow

The terrifying Illgraben debris flow on 29th May 2017. Still from a Youtube video by Pierre Zufferey.


The Illgraben site includes a warning system for debris flows.  It appears that this worked as planned – the video captures the flashing light of the warning system as the debris flow front moves through:-

terrifying Illgraben debris flow

Successful activation of the warning system for the terrifying Illgraben debris flow. Still from a Youtube video by Pierre Zufferey


A mudflow in Embu, Kenya

Of course landslides do not have to be this violent.  The Kenya TV news report below, from 25th May 2017, features a mudflow from Kanyakiri village in Embu, Kenya that appears to have caused massive damage to a tea plantation.  Note the deeply weathered red soils, similar to those from my post about Sri Lanka last week: