# Heavy rain and flooding in Japan

> Live situation record from CLSTR: https://clstr.news/situations/heavy-rain-and-flooding-in-japan
> Updated: 2026-08-15T00:15:49.000Z. Sources: 18. Developments: 2.

Heavy rainfall and flooding have impacted multiple regions across Japan. In the Ishikawa and Niigata prefectures, intense downpours and high tides caused road and farmland inundation, leading to transportation disruptions such as the suspension of JR Nanao Line services. In Niigata City, officials have emphasized disaster preparedness and drainage improvements following previous flooding.

Subsequently, unprecedented torrential rainfall in eastern Japan caused severe flooding and fatalities in Chiba Prefecture. The death toll has risen to at least nine people, with one person reported missing. The extreme weather, described by officials as “unprecedented,” saw Chiba record over 300mm of rain in 24 hours, marking its wettest August in 60 years.

The flooding has caused widespread destruction, with more than 1,000 homes inundated and dozens of buildings partially or fully destroyed. Approximately 20,000 households have lost power, and authorities are managing hundreds of evacuees in local shelters. Infrastructure damage is significant, including an estimated 1,200 vehicles abandoned on flooded roads. 

Transportation remains heavily disrupted, with thousands of travelers stranded at Narita International Airport and various rail and road services affected. In Chiba City, investigations are underway following a fatal flooding incident at an underpass after a drainage pump and an emergency generator failed to operate.

## Claims

- The death toll from the record rainfall in Chiba Prefecture has risen to nine people. (corroborated by 5 sources)
- Chiba recorded 300mm of rain in 24 hours, the highest August rainfall in 60 years. (corroborated by 3 sources)
- Approximately 1,200 vehicles were left abandoned on roads due to the flooding. (corroborated by 3 sources)
- More than 20,000 households experienced power outages. (corroborated by 3 sources)
- Over 1,000 homes were flooded, with many experiencing water above floor level. (corroborated by 3 sources)
- One man remains missing following the heavy rains. (corroborated by 2 sources)
- As of Saturday afternoon, 463 people were staying in 92 evacuation shelters. (corroborated by 2 sources)
- A drainage pump and a backup emergency generator failed to operate during the flooding of an underpass. (corroborated by 2 sources)

## Timeline

### 2026-08-15: Chiba flooding kills nine after unprecedented torrential rain

Nine people are dead and one is missing after unprecedented torrential rain hit Japan's Chiba Prefecture, causing widespread flooding, power outages, and thousands of travelers to be stranded at Narita Airport.

16 sources. https://clstr.news/cluster/japan-heavy-rains-cause-fatalities-and-flooding-in-chiba

### 2026-08-09: Heavy rain and flooding impact Ishikawa and Niigata regions in Japan

Heavy rain and high tides have caused flooding in Ishikawa, disrupting trains and roads, while Niigata officials urge resident self-preparedness as long-term drainage infrastructure projects continue.

2 sources. https://clstr.news/cluster/heavy-rain-and-flooding-impact-ishikawa-and-niigata-regions-in-japan

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Cite as: Heavy rain and flooding in Japan. CLSTR, https://clstr.news/situations/heavy-rain-and-flooding-in-japan