Record-breaking rainfall in Chiba Prefecture has killed at least four people and stranded thousands of travellers, with more than 22,000 households left without power as severe flooding disrupted roads and rail services during Japan’s busy Bon holiday week.

A woman wades through a flooded road near Chiba metro station on August 13, 2026, as heavy rain swept through the area [Philip Fong/AFP]

Record rainfall has killed at least four people and stranded thousands of travellers in Japan’s Chiba prefecture, east of Tokyo.

Areas of Chiba recorded upwards of 360mm of rain in 24 hours into Friday, flooding roads and rail lines during the Bon Buddhist holiday week, one of Japan’s busiest travel periods.

Those killed included a man in his 60s or 70s found floating on a flooded road and a 66-year-old woman trapped in her submerged car, the Chiba Prefecture Disaster Management Office said.

The third death was a man of unknown age found collapsed on the street, and the fourth a person of undetermined gender and age. A fifth person was feared dead and a sixth unaccounted for.

Soldiers have been dispatched to the area to help with relief efforts, officials said.

“This case was an extremely unusual situation,” Chiba Governor Toshihito Kumagai told reporters on Friday morning. “I have responded to many disasters in the past, but I have never experienced a case like this.”

More than 22,000 households were without power by 11am (02:00 GMT) Friday, according to Tokyo Electric Power.

Some 80 homes experienced flooding and officials say more than 230,000 have been advised to take shelter.

Japan’s Ground Self-Defence Force said it evacuated 4,000 people from Soga train station after they were stranded by the flooding for hours.

Thousands more people were stuck overnight at the Narita airport serving the Tokyo region, with trains out of the area stopped.

Services partially resumed Friday morning with delays, while flights in and out of Narita were operating normally on Friday, with many people returning home at the end of Japan’s Bon Buddhist holiday week. Hundreds of people took shelter overnight at the Chiba prefectural government building.

The Japan Meteorological Agency downgraded its most severe warning for heavy rain in more than a dozen municipalities in Chiba prefecture as rain subsided Friday morning but forecast more rain later in the day.

Photos and television footage showed widespread damage after daylight, with homes, cars and parts of railway tracks flooded with muddy water.