TOKYO – At least 20 people are feared dead after a mudslide washed away multiple homes in the seaside city of Atami on Saturday morning (July 3), with search and rescue operations continuing into the night.
Two bodies have been found and another 20 remain missing as at 6.30pm (5.30pm in Singapore). Atami mayor Sakae Saito estimated that up to 300 homes may have sustained damage.
Residents reported hearing a deep roar moments before black water mixed with soil and sand rushed down a hill at about 10.30am. The brunt of the damage occurred about 1.5km north of the Atami train station.
Atami, with its steep hilly terrain overlooking the sea, is densely packed with homes, hotels and inns. The city is a popular hot springs resort destination, and is less than two hours away from Tokyo by train.
Japanese Prime Minister Yoshihide Suga offered his condolences to the victims and said that saving lives was the top priority. The Cabinet Office has set up a crisis response team, while the Self-Defence Forces have been activated to help local police and firefighters in disaster relief.
Questions, however, have arisen over whether the deaths could have been prevented, as an evacuation order was not raised to the most urgent Level Five even as the city was battered by record-breaking torrential rainfall.
While it has since been raised to Level Five for the city’s entire population of 35,602 people, it had been a Level Three advisory at the time of disaster.
Saturday’s landslide had struck only after the rain eased, in what experts say is a geological phenomenon called “debris flow”. In such a situation, water-logged soil and fragmented rock rush down slopes, engulfing everything in their path and leaving behind thick, muddy deposits.
Associate Professor Yuki Matsushi of the Kyoto University Disaster Prevention Research Institute told Mainichi Shimbun newspaper: “The terrain of Atami is of volcanic rocks. Debris flow occurs several hours after the peak of rainfall, which is a characteristic of sediment-related disasters that are common in volcanic rock geomorphology.”
He added that, given the time lag, people should not let their guard down even after the rain has stopped.
A lingering seasonal rain front has brought torrential downpours in wide areas in east Japan, the Japan Meteorological Agency said. Precipitation records were reset at 30 monitoring points in five prefectures, including Tokyo.
Atami received 315mm of rainfall in the 48-hour period through 1pm on Saturday, which is more than the 242.5mm of rainfall that the city usually averages for the entire month of July.
In the 72-hour period through 11am Saturday, a record-breaking 790mm of rainfall was recorded in the mountainous resort of Hakone in Kanagawa prefecture, and 556mm in the city of Gotemba in Shizuoka prefecture.
Elsewhere, a bridge caved in in the city of Numazu in Shizuoka.
A landslide also occurred near the city of Zushi in Kanagawa prefecture, south of Tokyo. Two lanes of an expressway were blocked by debris. A car that was passing by was flipped over, though the driver was unhurt.
A man in his 20s was swept away by an overflowing river in the nightlife district of the city of Chiba, east of Tokyo, in the early hours of Saturday morning.
The torrential rainfall brought widespread delays and suspensions to regional train services – including to the Tokaido Shinkansen that connects Tokyo and Shin-Osaka via Atami – though most have since resumed service.