engleski

Extreme weather in Croatia during the 2017 fire season

Croatian Meteorological and Hydrological Service has operated the Canadian Forest Fire Weather Index System (CFWIS shorter FWI) to estimate fuel moisture and fire weather indices based on weather observations since 1982.The spatial distribution of mean monthly (MSR) and seasonal severity rating (SSR), as products of the FWI, for the 2017 were compared with long-term averages 1981-2010. Maps of MSR from April to October 2017 show the maximum MSR of 54.7 in mid-Adriatic in August 2017. The maximum is also the absolute maximum since 1960 when there are estimates of MSR. Compared SSR in 2017 with long-term averages, SSR was 1.5-2 times above average but in August it was 2-3 times above average in the whole Croatia. The wildfire risk are directly associated with long dry periods combined with the high air temperature, low relative humidity and strong wind. Therefore dry spells were analyzed for precipitation amount below 0.5 mm, 1.5 mm and 2.8 mm depending on the fuel materials: FFMC (Fine fuel foisture cod), DMC (Duff moisture cod) and DC (Drouth cod) respectively as well the warm and very warm spells with maximum daily air temperatures above 30 °C and 32 °C. In the conditions of above average warm spring and summer of 2017 and lack of precipitation in the winter, spring and summer periods, the longest and most pronounced warm (maximum of 39 days) and very warm (maximum of 15 days) periods appeared in the mid-Adriatic from the end of June to the first half of July and from the end of July to the first half of August 2017. The highest number of consecutive dry days for FFMC was 73 days, for DMC 78 days, and for DC 100 days. Therefore, 2017 was the most intensive fire season with more 4000 fires and 110, 000 ha burned area.

extreme warm and dry spells, wildfires, Canadian Fire Weather Index System

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