Extreme geomorphic events in the contemporary evolution of forested slopes in a Central European mountain range, the Sudetes

Forested slopes of the Sudetes have long been implicitly considered as stable under contemporary environmental conditions, with little geomorphic change throughout the Holocene. This view is difficult to sustain and this review-type paper brings together evidence that infrequent but potent surface processes locally cause significant remodelling of slopes and regolith removal or redistribution. These processes are debris flows, shallow and deepseated landslides, episodes of efficient linear water erosion and windthrows. All are triggered by exceptional meteorological events such as heavy rain or strong wind, but additional factors of slope steepness and suitable lithology play a role. Scarce database does not permit to firmly establish recurrence intervals of such events but they seem to occur at least once per decade (within the entire mountain range) for rain-induced phenomena and two-three times per century for wind-induced phenomena.