Recent Trends in Hail Precipitation for Administrative Districts of Bulgaria

Abstract

AbstractConvective storms, which produce hail, cause significant damage to agriculture, buildings, vehicles, ecosystems and even cause human casualties in many countries around the world, as well as in Bulgaria. The relief and geographical location of our country characterize it as one of the countries with the highest frequency of hail event in Europe. This study summarized the monthly and annual variations of hail days for each administrative district in Bulgaria for the period 1991–2020. The data used in the analysis include daily, monthly and annual number of hail days from the meteorological network of the National Institute of Meteorology and Hydrology for the period considered. A comparison of the frequency of hail for one meteorological station, representative for each district, for two periods (1961–1990, 1991–2020) was made. In the last 30 years, there was an increase in hail days in May, as well as in the relatively cold month of March for almost all regions. The obtained trend is statistically significant only for few districts. During the cold half of the year (October-March) there is an increase in hail events in almost the whole territory of Bulgaria, more significant for districts from South Bulgaria.KeywordsBulgariaHail variationsClimatology