An engineered slope reported to be 43 meters (141 ft) high that was stabilized by what appears to be tie-back anchors experienced a massive failure at the end of 2012. Dr. Dave Petley of the Landslide Blog made a few observations regarding the possible failure modes and also pointed out in a subsequent post some comments by a supposed 'expert'. But it seems virtually impossible to me to determine what caused this failure until more information comes out. [Source: The Landslide Blog. Image: The Landslide Blog]