The first visible clues to activity on the landscape have appeared since the middle of the 20th Century. Nevertheless the La Clapière landslide is assessed to have been active in depth for around 10,000 years.
The first historical witness to movement stands in the etymology of the name ’Clapière’ given to the slope. In fact, the name ’Clapière’ is derived from the Provençal term ’Clapasse’, which names a rockfall area. Moreover the archives of witnesses by persons who ’practised’ the slope, describe the ancient history (18th Century) with major indications of instability:
frequent block falls at the level of the SW lateral edge of the present landslide (along the Dailoutre valley) and the present peak scarp,
the occurrence of scarps and strain failures at the level of the present upper boundary of the landslide.
The comparison between the photos taken in 1938 and 1976 does indicate a stressed scarp (a few meters vertical displacement) at mid slope (elevation 1,700 m) and a massive rockfall fan just downstream to the Saint Etienne de Tinée village.
From 1976 to 1984, the slope is subjected to more and more important morphological disorders, in particular:
a large emphasis of the rupture of the top slope (vertical displacement greater than 10 m),
a progression of the rockfall source area upwards (elevation 1,500 m) and towards the center of the slope and the occurring of a new one at the foot, on the Rabuons side.
Moreover the slope foot also shows a fast progression generating the destructuration of the former road leading to the Saint Etienne de Tinée village.