Characteristics of Heavy Rainfall Disaster in the Kyushu district from July 19 to 21, 2003

Motoyuki USHIYAMA*


A heavy rainfall caused by a baiu-front (stationary front) occurred in Kyusyu district from July 19 to 21, 2002. In Minamata city, Kumamoto prefecture, an hourly precipitation of 91mm was recorded on July 20 and the total precipitation amounted to 428 mm. The highest 1 hour precipitation records in the last 23 years were revised at 3 observatories, and the highest 24-hour precipitation was revised at 4 observatories based on the data of the Japan Meteorological Agency. In this heavy rainfall, 23 persons were killed, 104 houses were destroyed, and about 7,800 houses were inundated. The largest human damage due to this event occurred in Minamata city, Kumamoto prefecture. While the residents were taking shelter, debris flow killed 19 people in the city. The evacuation issue by Minamata city was announced after the debris flow occurred. In Fukuoka city, 1,352 houses were flooded when the Mikasa River overflowed its banks. A flood disaster had also occurred in the city in 1999. In a hotel, a disaster prevention plan based on Internet real-time rainfall and water revel information was established after the disaster. Water sealing plates were installed according to this plan and this hotel escaped the present flood damage. It is important to examine methods of utilizing real time rainfall information.

Key words: heavy rainfall disaster, sediment disaster, real time rainfall information, Minamata city.

48-hour presipitation distribution maps

Hourly presipitation in the heavy rainfall areas

Debris flow disaster in Minamata City, Kumamoto prefecture.

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