Typhoon Dujuan leaves four dead in Japan, 45,000 homes without power as six go missing

Typhoon Dujuan left at least four people dead and 22 injured in Japan, and more than 45,000 households near Tokyo were still without electricity on Tuesday afternoon after the storm swept through the region, authorities said.

Three people died in Chiba prefecture and one in Kanagawa, both areas bordering Tokyo, according to the Fire and Disaster Management Agency. Search operations were continuing for six people reported missing after landslides triggered by torrential rain.

The typhoon moved away from Japan’s coast and out into the Pacific by morning, allowing authorities to lift or downgrade most heavy rain and landslide warnings. More than 460 houses were reported damaged, and utility crews were working to restore supply to the households still cut off in Chiba.

Although Dujuan weakened as it moved north-east, it dumped record rainfall on parts of the Tokyo region. Oshima, an island about 120 kilometres south of central Tokyo, recorded 832 millimetres of rain over 48 hours — more than double its average rainfall for the whole of September, public broadcaster NHK reported. In Tokyo’s Edogawa Ward, rainfall reached a record 282.5 millimetres in 24 hours.

In the capital, the storm had already forced one of the world’s biggest video game trade fairs to close early. Japan regularly experiences strong typhoons in the late summer and early autumn, and other storms this season have disrupted some events at the Asian Games being held in the country.

Chiba and Kanagawa lie within the Greater Tokyo Area, one of the most densely populated regions in the world, and include major ports, airports and commuter towns.

Typhoons are tropical cyclones — the name given to such storms in the western Pacific and Indian Ocean — and they draw their energy from warm ocean water. Japan’s typhoon season generally runs from May to October, with activity peaking in August and September, when the country is often struck by several storms in quick succession.

The country maintains one of the world’s densest networks of rain gauges, river sensors and weather radars, and municipal governments can issue evacuation advisories or orders when rivers rise towards flood level. Even so, landslides and flash floods can develop within minutes when rainfall is intense, especially in mountainous and coastal areas. Advisories for landslides are often kept in place after a storm passes, because waterlogged ground can give way without further rain.

Scientists say human-driven climate change is increasing the risk posed by heavy rain, because a warmer atmosphere holds more water vapour. Warmer sea surface temperatures also provide more energy for tropical cyclones, although any single storm is shaped by many factors.

Rainfall records at individual weather stations refer to the highest totals measured at that location since observations began; they do not mean the same amount fell across the entire surrounding area.

Figures released after such disasters are frequently revised as rescue teams reach areas cut off by flooding and landslides, and agencies continue to assess the full extent of the damage. Tuesday’s toll and damage estimates remain provisional.