Changes in the occurrence of the persistent seasonal snow cover in Slovakia in the period 1921/1922 - 2022/2023

Snow cover and its characteristics are among the meteorological indicators that are usually the most affected by the changing climate. In the complex natural conditions of Slovakia, this can mean the emergence of conflicting tendencies even within small regions. In connection with the geographical location of Slovakia, the influence of the greater continentality of the climate of eastern Slovakia, or more pronounced manifestations of the oceanic climate of the western and south-western regions of Slovakia, can also influence formation and durability of the seasonal snow cover (SC). Persistent seasonal snow cover is methodically defined as a period of continuous snow cover that can be interrupted for a maximum of 3 days during the given season. Time series of the daily snow cover depth used in this paper already reached a length of more than a hundred years, which can be a sufficient guarantee of an objective expression of detected changes in the occurrence of persistent seasonal snow cover. In connection with the general decrease of days with the persistent seasonal snow cover, which has not avoided the Central European region, the aim of this paper is to draw attention to the reduction in the occurrence of the persistent seasonal snow cover in Slovakia. It manifests itself in the form of a decrease in the number of days with snow coverat the beginning and at the end of the winter season and its instability during the main part of the season, in which the fluctuation of temperature conditions is accentuated. In the historical context, the shortening of the period with persistent seasonal snow cover in Slovakia began to manifest itself significantly in the second decade of the 21st century.