At least four people died in eastern Japan after heavy rain that left thousands stranded at one of Tokyo's main airports overnight and inundated roads and railways, authorities said on Friday.The torrential downpours late on Thursday triggered landslide warnings and power outages, with forecasters issuing the highest-level heavy rain warning for the Chiba region for the first time.Those killed included a man in his 60s or 70s found floating on a flooded road and a 66-year-old woman stuck in her submerged car, the Chiba Prefecture Disaster Management Office said.Roads were flooded in Oamishirasato, Chiba Prefecture after torrential rainfall. (AP: Kota Endo/Kyodo News)The third fatality 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.More than 360 millimetres of rain fell in 24 hours in parts of Chiba Prefecture, which adjoins the capital Tokyo, inundating roads and railways ‌during one of Japan's busiest holiday weeks.Heavy rain flooded the city of Sakura in Chiba Prefecture. (Reuters: Kyodo)Record-breaking rainfall of 115mm fell in just one hour in Chiba city and 97mm fell in one hour in Sakura, also a record for that city.The Japan Meteorological Agency downgraded its most severe warning for heavy rain in more than a dozen municipalities in Chiba Prefecture as rain subsided on 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."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."Hundreds of people were left stranded in Chiba station due to suspended train services."This happened all of a sudden so it was a complete surprise. The power is out so I'm worried whether I can open my business in the next couple of days," a woman in Chiba's Ichikawa city told NHK on Thursday.In Chiba city, hundreds of people ⁠spent the night under foil blankets at government ‌buildings serving as temporary evacuation ‌centres.As of Friday morning, more than 26,000 households across Chiba Prefecture were without power, the disaster management office said.Japan's Ground Self-Defense Force also said it dispatched buses to pick up about 4,000 stranded people who stayed overnight at the Soga train station, a local route that also serves Tokyo Disney. The theme park did not report any damage.Passengers stranded at major Tokyo airportThe transport disruption left about 7,000 people stranded at Narita International Airport, one of two main airports serving Tokyo, however all flights were scheduled to operate normally on Friday, an airport spokesperson said.Japan Airlines said some flights may experience delays but no cancellations were expected.Many trains to and from the airport were cancelled until Friday afternoon, the Chiba disaster office said.Passengers at Narita International Airport were stranded due to heavy rain. (Reuters: Kyodo)Users on social media said that airport staff handed out free water, food and sleeping bags."I never thought I'd spend the night at the airport but it is what it is and we are learning," one stranded air traveller told Japanese broadcaster NHK."We're never going to forget this trip," he said.AFP/AP/Reuters