Frequency and thickness of snow cover at the foot of the Babia Góra Massif in the winter seasons 1960/61 to 2014/15

Abstract

Abstract The aim of the study was to gain knowledge about changes in the nival conditions prevailing in the lower part of the Babia Góra massif in the winter, during the period from 1960/61 to 2014/15. The performed analyses concerned the daily snow cover thickness in the winter seasons of the years 1960/61–2014/15, and were based on data recorded by a meteorological station established by the Institute of Meteorology and Water Management – National Research Institute (IMGW-PIB) in Zawoja (697 m altitude). The study was focused on the period from the first to the last day of the appearance of the snow cover in the season. Based on long-term measurements carried out in in Zawoja, it was found that the average length of the occurrence of snow cover with the thickness of ≥ 1 cm was 104 days, which showed variability in individual seasons that ranged from 47 days in 2013/14 to 145 days in 1993/94. It was noted that the period of snow cover occurrence was shortened – from 118 days in the decade 1960/61–1969/70 to 96 days in the recent decade (2000/01–2009/10). The potential duration of snow cover was on average 157 days. The snowiest months were February and January, when snow cover occurred for 81% and 75% of all the observation days, respectively. The largest thickness of snow cover was recorded during these two months, with the maximum of 178 cm (January 30, 1976). In contrast, snow cover was not observed in July, August and September. The studied multi-year period was characterised by high variability of the winter snowiness index: from 1.61 in 2013/14 to 8.00 in 1962/63. In the period 1960/61–2014/15, in Zawoja, there was observed the distinct periodicity (16–19 years) with regard to the number of days with snow cover, the average and total snow cover and the winter snowiness.