Record-breaking rainfall hits western Honshu and Kyushu, causes fatalities and damage, Japan

On Saturday, July 1, 2023, parts of Western Honshu and the Kyushu region in Japan were hit with record-breaking rainfall, resulting in one confirmed fatality, two missing individuals, and extensive damage to over 270 homes. This extreme weather event has prompted evacuation orders in several municipalities.

Western Honshu and the Kyushu region in Japan experienced record-breaking rainfall on July 1, 2023, resulting in severe consequences, including one confirmed death, two missing persons, and significant damage to over 270 houses. As of 15:00 local time, the city of Yamaguchi recorded a record-breaking 332.5 mm (13.1 inches) of rainfall in 48 hours, while Yunomae town in Kumamoto Prefecture registered 469 mm (18.5 inches).

This extreme rainfall led to widespread damage, primarily in Yamaguchi Prefecture, where more than 270 houses were affected, according to the Fire and Disaster Management Agency. A man was found dead inside a washed-away car in the same prefecture, while a mudslide in Oita Prefecture resulted in a house being swept away, with authorities still attempting to reach the 70-year-old male occupant.

Heavy rain resumed on the evening of Sunday, July 2, 2023, in the Kyushu region, due to an active front, resulting in evacuation orders and a bridge collapse in Kumamoto Prefecture. As of Monday, July 3, several municipalities across Fukuoka, Saga, Kumamoto, Oita, and Miyazaki prefectures were under evacuation orders.

On July 3, the Japan Meteorological Agency (JMA) reported a linear precipitation zone in Kumamoto Prefecture. A linear precipitation zone comprises a line of cumulonimbus clouds that can remain stationary or pass over an area for several hours, often bringing heavy rainfall. The agency warns of continued rainfall in Kyushu, possibly leading to the formation of another linear precipitation zone and urges residents to stay vigilant against potential landslides and house flooding.

Downpours have been intermittently striking Kyushu and western Japan’s Yamaguchi Prefecture since June 29. The cumulative rainfall in Hita, Oita Prefecture, reached 683.5 mm (26.9 inches) by 10:00 LT on July 3. The weather agency predicts up to 200 mm (7.9 inches) of rain for Kumamoto Prefecture, up to 120 mm (4.7 inches) for Nagasaki Prefecture, up to 100 mm (3.9 inches) for Fukuoka and Oita prefectures, and up to 80 mm (3.1 inches) for Saga Prefecture in the 24 hours up to midday on July 4.

References:

¹ One dead and two missing as western Japan hit by heavy rain – The Japan Times – July 2, 2023

² Torrential rain in Japan’s Kyushu sparks evacuation orders, causes bridge to collapse – The Mainichi – July 3, 2023

Featured image: Collapsed Kaneuchi bridge in the town of Yamato, Kumamoto Prefecture, on July 3, 2023. Image credit: Yamato town government