CONTRIBUTION TO DEFINE THE BLIZZARD PHENOMENA TROUGHT CLIMATE STUDY IN SOUTHEASTERN ROMANIA
ABSTRACT. – Contributions to define the blizzard phenomenon through climate study in southeastern Romania. The definition of the phenomenon of blizzard implies two distinct aspects: the transport of snow on ground and the transport of snow at heights or also known as the actual blizzard. In order for a phenomenon to be defined as blizzard, it has to meet two mandatory conditions: strong wind (>15 m/s) and snow cover (previously deposited or associated with snowing phenomenon). The delineation between the two phenomena, respectively snow transport at heights as compared to the one on the ground is often subjective or difficult to assess (being determined visually by the observatories at the meteorological stations.) The topography of the place, the moment of day when the phenomenon is produced, the luminosity, the visibility landmarks, etc. can often times lead to the incorrect assessment of the phenomenon. The only parameter measured exactly (among the meteorological parameters that define the phenomenon) is the wind (parameter that is determined automatically by the sensors in the meteorological stations where they exist), aspect that might be a delineating factor when the occurrence of the phenomenon is estimated. The climatological analysis of the data derived from 19 meteorological stations located in the South-East of Romania, throughout a period of over 50 years (1961-2012) revealed the existence of the phenomenon of blizzard (transported on ground or at height), associated/not-associated to the phenomenon of snow, with a snow layer/without and at different intensities of the wind. Being a natural phenomenon with climatic hazard and negative impact on the environment and the human society, the correct delineation of the two phenomena might highlight the territories with increased vulnerability to its occurrence. Starting from those presented above, the hereby paper aims to make a detailed climatological analysis regarding the snow transport on ground and at height and their delineation based on the data given by the 19 meteorological stations placed in the South-East of Romania (1961-2012).
Keywords: blizzard, snow transport on ground or at height, wind, snow cover.