A Climatological Survey of Spring of 2019 Flood-causing precipitations in the western parts of Iran

In late March 2019, heavy rains occurred in Iran, which led to floods in several provinces of the country. In this paper, the spring floods of 2019 in the western basins of the country (Karkheh and Karun) have been investigated. These floods brought heavy losses to the country. Nation administration tried to dissect this event and know its causes and consequences. This experience showed that flood is an anthropogenic - physical phenomenon and it is naturally complex like all other human phenomena; Complex, in the sense that it is the result of the interaction of many different components. Here, we have examined partly one of the components of this complex phenomenon, that is, the part of precipitation from the climatological point of view. This investigation showed that the intensity of rain in the spring of 2019 did not exceed the historical events, but the amount of rain received by the basins was unprecedented. Therefore, from a climatological point of view, heavy rainfall and the location of the core of rainfall played the most important role in the occurrence of this flood. The amount of rainfall in the Karkheh and Karun basins in 9 days was equivalent to about 70% of the annual rainfall of these two basins. The establishment of the rain core in the eastern steep part of the basin has also contributed to the intensification of floods.