Empirical thresholds for the initiation of landslides can be loosely defined as global, regional, or local thresholds. A global threshold attempts to establish a general (“universal”) minimum level below which landslides do not occur, independently of local morphological, lithological and land-use conditions and of local or regional rainfall pattern and history. Global thresholds have been proposed by Caine (1980), Innes (1983), Clarizia et al. (1996), Crosta and Frattini (2001), Cannon and Gartner (2005) and by Guzzetti et al. (2007). Regional thresholds are defined for areas extending from a few to several thousand square kilometres of similar meteorological, climatic, and physiographic characteristics, and are potentially suited for landslide warning systems based on quantitative spatial rainfall forecasts, estimates, or measurements. Local thresholds explicitly or implicitly consider the local climatic regime and geomorphological setting, and are applicable to single landslides or to group of landslides in areas extending from a few to some hundreds of square kilometres. Regional and local thresholds perform reasonably well in the area where they were developed, but cannot be easily exported to neighbouring areas (Crosta, 1989). Global thresholds are relevant where local or regional thresholds are not available, but may result in (locally numerous) false positives, i.e. prediction of landslides that do not occur.