Tropical Storm Jangmi cut through a large portion of Honshu on Wednesday, producing conditions that are expected to generate claims across several insurance lines.
The storm, the sixth named storm of the 2026 Pacific typhoon season, brought sustained rainfall, flooding, and high winds before tracking northeast and away from the Japanese mainland by Wednesday afternoon. Nationwide, 23 people sustained injuries and 57 houses were damaged, the Fire and Disaster Management Agency confirmed, according to The Japan Times. Evacuation orders at Level 4 were issued for residents in parts of Tokyo, Kanagawa, and Chiba prefectures before authorities lifted them later in the afternoon.
The most severe alert of the day came from the Japan Meteorological Agency and Wakayama Prefecture, which jointly declared a Level 5 special flood warning – the highest level in Japan’s warning system – after the Kozagawa River overflowed and inundated nearby homes. The warning was later reduced to Level 2, though officials continued to call on residents to stay alert for further rises in river levels. A section of National Route 371, which runs alongside the river, also gave way during the event, The Japan Times reported.
In the Kanto region, floodwaters reached 30 centimetres deep at a road intersection in Kawasaki’s Saiwai Ward, and the area near Kawasaki Station was temporarily submerged, according to NHK. A stretch of national highway in Tokyo’s Ota Ward was also covered by water. At 4pm, the storm was positioned roughly 90 kilometres east-southeast of Choshi in Chiba Prefecture, moving east-northeast at 50 kilometres per hour. Central pressure stood at 985 hectopascals, with sustained winds of 25 meters per second and gusts reaching 35 meters per second, The Japan Times reported. The Japan Meteorological Agency projected up to 120 millimetres of additional rainfall across the Kanto-Koshin and Tohoku regions through Thursday noon, and cautioned that high waves would remain a concern along eastern Japan and Tohoku through Thursday.
The disruption to essential services compounded the physical damage from the storm. Tokyo Electric Power Co. Holdings recorded more than 12,000 homes without electricity across the Kanto-Koshin region by Wednesday evening, according to The Japan Times. In Ome, the Tokyo Metropolitan Government reported that 1,800 households lost access to water, with full restoration likely taking several days.
Rail operations across the capital region were curtailed from the morning. East Japan Railway Co. halted service on several lines before gradually restoring most of them through the afternoon and evening, The Japan Times reported. On certain routes, including the Hachiko Line between Haijima and Komagawa stations, tree branches caught in overhead wires forced additional stoppages. A number of lines did not resume at all during the day, and limited express services across the Kanto area were also heavily affected.
Air travel saw considerable disruption. According to NHK, major Japanese carriers cancelled approximately 760 domestic flights and more than 90 international flights. The Japan Times reported that Japan Airlines cancelled 292 domestic and 37 international flights, while All Nippon Airways cancelled 232 domestic and 55 international flights. Skymark, Solaseed Air, Peach Aviation, Jetstar Japan, Air Do, StarFlyer, Japan Transocean Air, Fuji Dream Airlines, IBEX Airlines, and Spring Japan recorded additional domestic cancellations – 70, 37, 32, 31, 28, 22, five, four, four, and two flights, respectively, according to The Japan Times. Postal services were also halted in Tokyo and 13 other prefectures.
The combination of property damage, infrastructure failure, utility outages, and transportation disruption positions Jangmi as a multi-line claims event for the Japanese insurance market. Property and casualty underwriters, aviation insurers, and business interruption carriers are among those likely to begin preliminary loss assessments in the near term as policyholders document the extent of their losses. The storm also surfaces a structural issue that insurers operating in Asia-Pacific have tracked for decades. According to Munich Re, natural disasters across the region have produced approximately US$2.4 trillion in total losses since 1980, accounting for roughly one-third of global natural disaster losses over the same period. Despite that volume of loss, the protection gap in Asia-Pacific sits at 88% – far above the global average of 67% – meaning that only a fraction of losses are ultimately covered by insurance. Japan, as a comparatively mature market, carries higher penetration rates than many of its regional counterparts, but individual storm events continue to stress coverage adequacy across property, casualty, and specialty lines.
The most acute phase of the storm appeared to pass by Wednesday afternoon as Jangmi moved offshore. The Japan Meteorological Agency maintained advisories for landslides, elevated river levels, and coastal waves into Thursday, particularly across eastern prefectures and the Tohoku region. Insurers with policy exposure across the affected areas are expected to open formal claims processes in the coming days as assessments of property, vehicle, and business losses get underway.
