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Flash floods are one of the major types of natural hazards. Such type of the floods is a relatively rare event on the local scale however, the climate change together with an increase of land use and deforestation in some areas can reflect in an increase of such type of extreme floods. Even the urban areas are also prone to flooding in short periods of time and sometimes rainfall (from the same storm) over an urban area may cause faster and stronger floods than in the suburbs or the countryside. With regard to climate change, the increase of the risk of loss of life and material damages may occur in such areas. The main objective of the paper is to describe, investigate, post-event analyze and compare causalities, culminations, courses and consequences of the four summer flash floods on small basins in Slovakia since 1998. The first one occurred in July 1998 on the Malá Svinka stream in east Slovakia; the second two occurred in June 2011 on the Gidra stream and on the Parná stream in the Small Carpathians and the fourth flash flood occurred in July 2014 in the Malá Fatra National Park in Vrátna Valley. Analyses of the every extreme situation play an important role as an information source in determining the culmination and the course of the flash floods in ungauged basins together with information about geology, topography, vegetation and precipitation in the development of hydrological models for flood risk management. The time–space scales of the occurrence of flash floods are small compare to the rain sampling characteristics and discharge measurement networks. Comparison of natural extreme events from different geographical regions and different rainfall events can provide comprehensive information about their regimes, threats and disastrous effects. [ABSTRACT FROM AUTHOR]

Climate change is acknowledged as the world's significant environmental predicament. Rainfall and temperature have been widely studied in correlation with climate change. This paper demonstrates the result of the trend analysis of rainfall variables over the period of 1984 to 2013 and temperature variables over the period of 1979 to 2013 in Brunei Darussalam. Mann-Kendall trend test was applied to analyse and detect trends for the variables. This study revealed that the observed rainfall has a statistically significant increasing trend with increasing rainfall duration and decreasing intensity. The annual rainfall has increased significantly at a rate of 26.16 mm per annum. Mann-Kendall test for rainfall data reveals an increasing trend at confidence level of 95% for the annual total rainfall and confidence of level 90% for of annual maximum rainfall. The observed temperature also exhibits a statistically significant increasing trend at a rate of 0.031°C per year. Results of Mann-Kendall test for temperature data indicate a positive trend at a confidence level of 99.9% for the annual average temperature, average day time temperature, minimum day time temperature, average night time temperature and minimum night time temperature and at a confidence level of 95% for maximum night time temperature. The progressive effect of both the observed rainfall and temperature changes will contribute to greater surfaces run off and create flooding problem. Too much rainfall will threaten slope stability while dry periods of increased temperature will cause soil erosion. [ABSTRACT FROM AUTHOR]