Analisys of recent snow volumic mass and elevation of the threshold of natural skiability (lan) in the frioulan alps

The Friulian Alps show peculiar meteorologica and climatic features, deriving also from their geographic position between the northern Adriatic Sea to the South, the main Alpine watershed to the North (Tauern Alps) and the Carpathian belt to the East. Furthermore, there are many topoclimatic situations in relation to the geographic setting of the valleys carved between the main reliefs. This makes the Frioulian territory among the wettest in the entire Alpine region, with very abundant snowfall in relation to the moderate average altitude. Thanks to the availability of continuous and fairly homogeneously distributed historical series, a nivological characterization was carried out at the regional scale, with particular attention to the trend of the density of fresh snow, of the number of days with snow thickness higher than 30 cm and the consequent average elevation of the threshold of 100 skiable days (LAN). The ten snow fields under examination are located at elevations between 603 m. (Claut, Carnic Prealps) and 1843 m. (Rifugio Gilberti, Julian Alps); the analysed timespan goes from the winter season 1990-91 to the 2018-19. Surprising data resulted from this analysis. First of all, we noted that the volume mass (Kg /m³), which cannot be correlated with altitude, tends to a very light decrease (about 1.3 km/mc for year) in all the recording stations: this seems to be in contrast with the strong thermal increase that is occurring also on the Frioulian Alps (about 1.1°C in the same time span). Therefore, it’s very probable that in the last few years the thermal characteristics have changed, maybe together with the main origin of the air masses bringing snow in the study area. We also noted for all the stations an increase in the number of days with Hs> 30 cm: consequently, the average elevation of the limit of 100 days with natural ski possible is at about 1780 m a.s.l. and tends to decrease by about 7 meters per year (14 m in the nearby Slovenian Alps), even though it cannot be correlated with the aforementioned positive variation in temperatures and is in disagreement with the corresponding signals calculated for the northern side of the Alps.