Beyond the Visitor Centre, the Masareit landslide is clearly visible on the right, affecting the northern slope of Monte Terzo and the effects of which extend to the Bût Torrent, in the area of Laghetti. It is thought that the collapse of the rocky slope, involving about six million cubic metres of material, was triggered after the retreat of the ice masses that descended along the valley and the consequent rapid easing of the glacial pressure on the mountainside. The last glacial tongue to occupy the Bût valley dates back to about 15,000 years ago. In the 1980s, as a result of ongoing subsidence, it was necessary to refurbish the SS52bis, work which seems to have stopped all movement of the landslide.