Hydrotechnical facilities which are used for prevention/mitigation of floods and irrigation should be designed under considerations of meteorological conditions as well, primarily precipitation, thus reducing the climate risk. The knowledge of the causes for these phenomena is the basis for forecasts of potential conditions of hydrogeological disasters. This paper analyzes the quantity (design parameter) and causes (forecast input) of short-term precipitation extremes in Istria. The ombrographic data were collected from four meteorological stations: Abrami, Pazin, Pula and PoreE. The basic characteristics of weather types are presented by ground-level field of air pressure and at 850 hPa. The expected maximums for different return periods were estimated by the application of the General Extreme Value distribution (GEV distribution) on the annual precipitation maximums of 2-hour duration. On average, heavy short-term precipitation mostly occurs in the summer, with similar regional variability. The expected maximums are higher in the Istrian inland than on the coast, with deviations increasing for some durations in correlation with the increase in the return periods. These occurred mostly along the cyclonal front (type N-1) (26% cases in the inland - Abrami and 31% cases on the coast - Pula). This cause was followed by the low pressure valley type (Abrami-dol(2) 12%, Pula dol(1) 14%), and, slightly unexpectedly, ground-level non-gradient cyclonal field in as many as 11% cases. Two cases of rain episodes preceding floods in Istria were analyzed.
