###### Abstract
Other authors have also studied snow variables such as snow cover fraction [38], SWE [39], or albedo [40] by using microwave passive sensors instead of active ones. The coarse spatial resolution is the main drawback of these sensors when analyzing snow properties in mountain areas [41]. More specifically, microwave sensors are able to detect the presence of liquid water in the snow cover. This existence of liquid water generates high dielectric losses that provoke a significant reduction in radar backscatter [42]. Recent studies have shown that these losses are more significant and detectable in cross-polarized VH [43; 44]. Moreover, in [43], it is concluded that minimum SAR backscattering is reached at the end of the ripening phase, or in other words, at the beginning of the melting-runoff phase. At that moment, all liquid water content is held in the snowpack and starts to be released. From this onset, a monotonic increase in the backscattering is found until the snowpack is melted [45]. Active sensors are commonly used in local scale application. In particular, the new Sentinel-1 (S-1) SAR constellation, which has a dual polarization capability, very short revisit times, high spatial resolution, rapid product delivery, has open access for all imagery [46], and has become the most common source used in different applications that exploit wet snow information [19; 47; 48; 49]. From a water resources perspective, finding a relationship between this onset and the streamflow response can help forecast streamflow behavior due to runoff melting [50; 51]. In fact, the actual warming situation is altering this timing and increasing the need of a correct representation of this onset [52; 53]. However, the paths followed by runoff melting water for reaching the stream are multiple and difficult to differentiate [54]. In general, runoff melting water after leaving the snowpack arrives at the upper part of the soil [55]. From there, meltwater infiltrates the soil and/or accumulates to form a saturated zone at the base of the snowpack, moving toward a surface-water body following different paths that are conditioned by soil characteristics [56]. If soil is unsaturated and the water table is low, the water Infiltrates and moves stream ward as a subsurface flow. On the contrary, if the soil is close to the saturation state, meltwater accumulates to form a basal-saturated zone that develops within the snowpack through which water flows toward the stream [11]. One can therefore conclude that melting dynamics are directly linked to the baseflow response of the catchment [57]. Few studies have connected the dynamics of wet snow and its impact on water availability [58]. In addition, most of them were carried out in environments where the snowpack normally is well consolidated during the winter. That is, the snowpack has thick depths and generally a unique snowmelt cycle during the springtime. On the contrary, Mediterranean mountains, located in semi-arid regions, are unlikely to have just one accumulation-melting cycle and suffer such slow transitions [2; 4; 5; 59]. Indeed, in these areas, the main characteristics are generally quicker snowpack changes, several melting cycles throughout the year, and perhaps the loss of some of the three theoretical melting phases due to this quick response [3; 60]. This higher Mediterranean frequency of accumulation-melting events will have a different characterization compared to those previously analyzed in other temperate regions, such as the Alps [35; 43; 61]. Therefore, there is still a gap when analyzing wet-snow dynamics in semi-arid regions. There is the need for a deeper understanding of wet-snow dynamics that assesses if the outcomes found in other regions for the spring melting are reproducible in the rest of the melting cycles which occur throughout the snow season.