A number of towns in Western Japan were submerged in flood waters due to heavy rain that hit the regions of Kansai and Chugoku on Sunday. Urban places, despite drainage systems available, were also flooded. As 27.5 mm of rain fell within just a 10 minute period, even downtown Osaka’s Chuo Ward was besieged.
In Osaka’s Kita Ward, areas around Hankyu Railway Umeda Station were also affected. Including Umeda District, shopping malls were flooded, leaving business owners to close shops. “I had never experienced such a massive flood before,” said a 58-year old drugstore manager. His store was located above floor level. Osaka Airport in the city of Toyonaka had 66 mm of rainfall within an hour. Together with Osaka, Suita and other cities, 26 houses suffered from flooding above floor level. Meanwhile, 202 establishments were immersed in flood waters below floor level. In Hyogo Prefecture, cities like Amagasaki, Ashiya, and Nishinomiya had more than 70 houses that suffered from a deluge of water.
Underground passes from the prefectures of Osaka and Hyogo were also flooded. In Higashina Ward, the underground pass of JR Settsu-Motoyama Station was reported to be submerged in 60-70 cm of flood waters. Some of the station’s staff even had to carry some passengers on their shoulders just to pass through. The JR Sanko Line was suspended when a bridge near Inbara Station in Shimane Prefecture was washed away. The line connects Gotsu in Shimane Prefecture and Miyoshi in Hiroshima Prefecture. However, passengers from both cities are unlikely to avail the services of the lines any time soon. Rainfall near Tsuwano in Shimane Prefecture reached a 100-millimetre record within one hour.
“The number of cases of localized torrential rain over a short period has been increasing. Even if shopping districts are equipped with draining systems, they cannot sufficiently drain water from torrential rain during a short period if the places are situated in lowland areas, occasionally causing a flood,” Professor Keiichi Toda from Kyoto University said. The drainage system in urban places, which include entertainment districts, is designed to manage only up to 50-60 mm of rain fall in an hour. However, the Sunday rain was too much for the drainage facilities available at the time.