Analysis of the effect of Tropical Cyclone Phet on the occurrence of heavy rainfall and floods in Chabahar, Iran

Abstract

On the first day of June 2010 a very severe tropical storm occurred in the North Indian Ocean near the Arabian Sea, which was named Tropical Cyclone Phet (TCP). During the 7‐day period for which it was active, the intensity of TCP reached category 5 on the Saffir‐Simpson hurricane scale. On 4 June 2010 at 2130h local time (1700 utc), TCP hit the southeast of Sistan and Baluchestan Province of Iran and, more specifically, the Port of Chabahar. Chabahar received 109.5mm of rain, resulting in economic and social damages. The storm caused substantial physical damage including the destruction of water and electricity infrastructure, flooding, the blocking of roads by debris, and structural damage to roofs and buildings in rural areas over much of the Sistan and Baluchestan Province.The peak activity in Chabahar was between 0330 and 2130h on 5 June 2010, when heavy rainfall occurred due to warm sea surface temperatures and favourable upper‐level environment at 850 and 700hPa levels.Synoptic analysis shows that the existence of low pressure at sea‐level associated with a deep trough with its axis passing through the vicinity of Chabahar station were the main reasons for heavy rainfall on 5 June 2010 in Chabahar.A strong upward convective motion combined with considerable moisture convergence from Sea of Oman and the Arabian Sea produced a warmed and moistened boundary layer over the region.The moisture convergence at 0330 and 2130h in the lower troposphere shows that, in most cases, the moisture flux convergence maxima coincides with the cyclone centre over the Sea of Oman, which flows to Chabahar.