Crystalline rocks are resistant to weathering and alteration; mica-schists easily discompose on the schistosity plans, but they resist to alteration; sedimentary rocks are attacked by dripping, gully formation, torrentiality and landslides.
It has a crucial role in the current morpho-dynamic by reducing or stopping the processes of pluvio-denudation, torrentiality, collapse and sliding.
Besides the heavy rains, the flash floods occurrence was caused by: the rock friability, the high degree of
torrentiality and the nearly circular form of the basin, allowing the fast concentration of liquid and solid flows.