Horizontal Precipitation Gradients in Alpine Valleys of Northwestern Slovenia

Mountain landscapes are the areas characteristic for a great spatial variability of precipitation amounts. On the windward sides of orographic barriers there is intense rising of air, and on the lee sides air descends. The intensity of the two processes is manifested in great differences in precipitation amounts at short distances. Although the network of precipitation stations is the densest in the Alps of all mountain regions in the world, precipitation regime at the micro level continues to be poorly known at many a place. Precipitation stations in mountainous landscapes are the most numerous in lower-lying and settled areas, whereas they are rather few in the high-lying areas. Also the accuracy of measurements is problematic in the mountains. As a result, the information on precipitation regime is inadequate right in the areas with the largest precipitation amounts. This means that the estimation of water balance is inadequate, and it is difficult to forecast the precipitation-related processes, such as torrential floods, landslides, avalanches, and the like. The present paper deals with horizontal precipitation gradients in the Alpine valleys of Planica, Krnica and the stream Beli potok which are all situated in the north-western part of the Slovenian section of the Julian Alps.