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In a warmer climate, significant variations in the snow regime are expected. Thus, it is crucial to better understand present‐day snow cover regime, its duration and thickness, in order to anticipate future changes. This work presents the first characterization of snow patterns in the Catalan Pyrenees based on 11 snow stations located in high elevation areas (>2,000 m). Here, we examine spatio‐temporal evolution of the daily snow depth and new snow height (HN) since the earliest 2000s to 2020. In addition, we analyse the different synoptic patterns that cause HN events in the study area as well as the low frequency climate modes on the different stages of the snow season. Our results show evidence that the measured snow amount differs considerably between the western and the eastern Catalan Pyrenees independently of the considered elevation. While the eastern part has an average seasonal cumulative HN of 278 cm, the western sector gets almost twice (433 cm). Nonetheless, the onset of the snow melting does not show substantial differences, being primarily ruled by the elevation in both areas. The longest snow records (Núria, 1971 m) point to an increase of HN from 1985 to 2020, a trend which is also observed in most stations from 2000 to 2020. Nevertheless, some stations of the N western fringe record negative trends associated with the low frequency variability of the Western Mediterranean Oscillation (WeMO). Results also indicate that the NW Atlantic low‐pressure systems are the circulation weather types that provide more abundant HN in the majority of snow stations. The Atlantic advections are more frequent in autumn and winter, while the Mediterranean advections provide more intense and recurrent HN in spring. The atmospheric circulation is basically ruled by the East Atlantic/West Russia and the WeMO teleconnection patterns. [ABSTRACT FROM AUTHOR]

ABSTRACT In this study we analysed the spatial distribution of the long-term average and interannual variability of the number of snow days ( NSD) and the number of precipitation days ( NPD) in winter ( DJFM) in the Spanish Pyrenees, using data from 38 meteorological stations for the period 1981-2010. The interannual variability of the NSD and the NPD in winter was related to the frequency of weather types over the Iberian Peninsula. Data from six stations were also used to analyse a longer time period (1961-2013) to confirm the consistency of the results obtained during the main study period (1981-2010). The results indicated that the NPD is only influenced by the distance to sea whereas the NSD is determined by elevation and distance to the sea. A high frequency of west (W), northwest ( NW) and cyclonic (C) weather systems led to a high NPD in winter across the entire study area, whereas the frequency of north (N) weather types was only correlated with the NPD at the most westerly stations. For the NSD there was a gradient from the Western Pyrenees to eastern areas, mainly explained by the frequency of N weather types in the former area, and high frequencies of NW and W weather types associated with the latter. For most stations there was no significant trend found in the NPD or the NSD for the 1981-2010 period. However, a slight decrease was found for stations strongly correlated with NW weather types, and a slight increase was found for stations strongly correlated with the C weather type, which was related to a decreasing (increasing) frequency of NW (C) weather types during the same period. Analysis of the 1961-2013 and 1971-2000 time slices using a smaller subset of stations revealed a similar relationship between weather types and the NSD. This indicates that the 1981-2010 period is sufficiently representative to describe the relationship of the NSD and the NPD to weather type frequency. However, the study period chosen can markedly influence the trends observed, as the results showed a statistically significant decrease in the NSD for the 1971-2000 period, but no significant trends for the 1961-2013 and 1980-2010 periods. [ABSTRACT FROM AUTHOR]

• Pyrenean glaciers have a negligible contribution to water resources in the región. • Discussed paper oversimplified understanding of the climatic andhydrological conditions of the study area • Discussed paper has limited to provide a meaningful contribution to water scarcity problems on the Pyrenees region [ABSTRACT FROM AUTHOR]

As with other mountain areas in Europe, the subalpine belt of the Central Spanish Pyrenees (approximately 1600–2200 m a.s.l.) has undergone constant deforestation since the Neolithic era and particularly during the Late Middle Ages, in favour of livestock management and grazing in summer. This furthered the rise of transhumance between the lowlands and the highlands. The abrupt change in land cover triggered a variety of geomorphic processes and landforms that partially contributed to land degradation and an increase in erosion and sediment yield: shallow landslides, solifluction lobes, soil creeping, terracettes, parallel deep incisions (henceforth: gullies) and stone-banked lobes. The main factors explaining the location of the various landforms are elevation, gradient, aspect, plant cover, soil characteristics, and the topographic index. The statistical analysis clearly separates two types of landforms: (i) shallow landslides, solifluction lobes, and areas of soil creeping, located at relatively low elevations, deep soils and fairly gentle gradients; and (ii) terracettes, gullies and stone-banked lobes, which are generally found at high elevations, on thin soils, north-facing slopes and steep gradients. The declining livestock pressure from the beginning of the 19th century, and particularly from the mid-20th century, explains the progressive re-colonization of the subalpine belt by forest and the reduction in shallow landslides over the last few decades. Most likely, this forest recovery will continue in the near future, with the hydrological, geomorphological and biogeographical consequences still being far from understood. • Deforestation in the subalpine belt occurred mainly in the Middle Ages to favour the transhumance systems. • Deforestation has induced the triggering of a variety of land degradation processes. • The spatial distribution of landforms is related to topographic factors and soil depth. • Current reduced grazing results in forest expansion and a declining number of shallow landslides. [ABSTRACT FROM AUTHOR]