More than 20 missing in Joso, north of Tokyo, after days of torrential rain

More than 20 people are missing in a town north of Tokyo following days of torrential rain which weather experts said occurred just once every half a century.

As the rescue effort continued in Joso, the town of Osaki, was inundated after a river burst its banks on Friday morning. Japanese media reports said 80 Osaki residents were stranded when the breach sent water levels shortly before dawn.

Heavy rain caused by Typhoon Etau earlier this week caused flooding and landslides throughout Japan, forcing the evacuation of more than 100,000 people and causing widespread disruption to rail services. Three people have been confirmed dead, but the death toll could rise once water levels drop and rescue workers are able to properly gauge damage in the worst-affected areas.

Fears that rising water levels could threaten the city of Sendai prompted authorities there to advise - though not order - more than 400,000 residents to leave.

Etau has moved out into the Sea of Japan but continued to generate record levels of rainfall in several parts of the country.

The deluge also caused leaks of rainwater at the ruined Fukushima Daiichi nuclear power plant after heavy rain overwhelmed drainage pumps. The rainwater may have come into contact with huge quantities of radioactive water - which becomes contaminated after it is used to cool melted fuel - being stored in tanks at the site. The plant’s operator, Tokyo Electric Power, said it did not know how much tainted rainwater had flowed into the Pacific ocean, but a spokesman said tests conducted earlier this week showed the incident had “no effect” on the sea.

In Joso, 56 kilometres (35 miles) north of Tokyo, about 700 people were left stranded overnight after the Kinugawa river burst its banks along a 140 m stretch, sending a wall of water coursing through the town. The breach was the first in Joso for more than six decades.

Kyodo News reported that the flooding had inundated 6,500 homes and spread over more than 30 sq kms

Akira Motokawa, an evacuation official in Joso, told public broadcaster NHK that rescuers have been unable to keep up with the volume of calls for help.

In scenes that brought back memories of the March 2011 tsunami disaster, torrents of muddy river water wrenched homes from their foundations and submerged cars and farmland. Dramatic TV footage showed members of Japan’s self-defence forces plucking stranded residents from the roofs of buildings and vehicles.

The mayor of Joso, Toru Takasugi, said on Friday that 22 people were unaccounted for, while hundreds were still waiting to be rescued.

More than 30,000 of Joso’s 65,000 resident were ordered to flee their homes on Thursday, but hundreds more were left stranded. By late last night, more than 3,500 people were staying in evacuation centers, schools and other public buildings. Soldiers were delivering food, blankets and water to about 780 people who were stranded but did not need to be rescued.

In Osaki, a town in Miyagi prefecture about 200 miles north of Joso, military personnel began a second major rescue operation from the air after a river burst its banks on Friday morning.

Miyagi experienced record levels of rainfall on Friday morning, with heavy rain expected to continue until around noon there and in other parts of north-east Japan.

Takuya Deshimaru of Japan’s Meteorological Agency described the situation in Miyagi as “abnormal” and warned that the area was still in “grave danger”.

Weather officials and TV presenters repeatedly told residents in flooded areas to continue calling for help and not to attempt to escape by themselves. Those still able to evacuate were instructed to leave their homes in pairs or groups.

Military helicopters have been involved in several dramatic rescues of stranded residents. In one, a soldier was seen repeatedly lowering himself onto a building to rescue what appeared to be a family of four.

Another helicopter plucked a man in his 60s to safety after he had spent hours holding on to a utility pole, with the water raging around him.

Hisako Sekimoto, 62, who was lifted to safety on Friday morning, said she had spent the night on the second floor of her flooded house with her husband and three cats. “There was no time to escape – all we could do was go upstairs,” said Sekimoto, who at one point was up to her neck in water. “I kept praying the water wouldn’t come upstairs.”

Reiko Yamaji was one of dozens of people stranded at a supermarket, part of which was submerged. “We spent the night in the car parked on the rooftop parking lot,” the 75-year-old said. “The water supply had been cut and the toilets were out of order, but I’m so glad we all survived.”