The screes are the result of interaction between pre-existing rocks and exogenous agents, forming by mechanical disintegration processes, mainly due to cryoclastic (gelivation) processes. Cryoclastic processes are generated by the pressure exerted by water from pores or cracks and microcracks of the rocks. The result of these processes is known in the literature as cryo-nival relief. The main representatives of the cryo-nival relief are the screes; these are detritus mobile rocks, with angular ranges of various sizes (unsorted). This scree, in most cases, are areas that are unaffected or less anthropically affected; they represent habitats with certain microclimatic peculiarities, named mesovoid shallow substrate (MSS) or shallow subterranean habitats (SSHs) by the specialists. These terms being outlined and being used more and more frequently since the 1980s. One of the most important peculiarities of the MSS is represented by the high relative humidity values, a main ecological factor that depends on the interclastic porosity but also on the microporosity of the clasts that are part of the scree. Moreover, the processes of chemical and biochemical alteration are dependent on the presence of water in the rocks and therefore, indirectly, on porosity. For this reason, we examined the porosity of limestone clasts belonging to the scree. The generation of the scree itself, disgregation process on the masses, depends on the geomechanical characteristics of the rocks from which the nude slopes are made, how rock behaves in the cryoclasting processes, which is fundamentally influenced by porosity.