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Heavy rainfall and flooding risks in Japan

Updated 4 times since CLSTR started tracking revisions of this situation.

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2026-10-06 21:17 UTC → 2026-10-11 20:48 UTC · added removed

Heavy rainfall and sudden “guerrilla rainstorms” in Japan have led to significant safety risks and infrastructure concerns. In Chiba Prefecture, record-breaking rainfall in mid-August 2026 resulted in over 3,000 vehicles becoming stranded on public roads due to flooding. Safety assessments indicate that deep water poses severe risks to drivers, noting that water depths of 60cm can cause engines to stall and external pressure can make car doors impossible to open. In response to these risks, the Japan Automobile Federation (JAF) advises motorists to avoid entering flooded roads entirely. To prepare for potential entrapment, the Ministry of Land, Infrastructure, Transport and Tourism and the Yamaguchi Prefectural Police recommend carrying an emergency escape hammer, noting that drivers should aim for side windows rather than the windshield. hammer. The Tokyo Disaster Prevention handbook suggests that if a hammer is unavailable, using a vehicle’s headrest can be used to break glass by inserting the metal rods into the gap between the door and the window. if a hammer is unavailable. In late August 2026, following Level 5 heavy rain warnings, the JAF Fukui branch reported approximately 211 rescue requests for submerged vehicles, roughly triple its usual volume. JAF experts advise drivers to turn back if water reaches approximately 15 centimeters, as road markings and open manholes become difficult to detect. For larger vehicles, water reaching the halfway point of the tires (approximately 30 centimeters) poses a high risk of engine failure or loss of control. Authorities have emphasized increasingly focused on the danger of underpasses, where drowning accidents frequently occur. underpasses. Following a fatal accident in Kashima, Iwaki City, the Ministry of Land, Infrastructure, Transport and Tourism released new guidelines requiring road managers to categorize underpasses into four risk levels. Proposed levels and implement measures include installing like remote barriers and electronic signage signage. In Kyoto, residents in areas like Ukyo-ku have begun using digital platforms to prevent entry, with proactive traffic restrictions encouraged warn neighbors against entering underpasses during ‘Level 4 Heavy Rain Danger Warnings’. heavy rain. A Kyodo News survey revealed that at least 134 vehicles have been submerged in underpasses across 33 prefectural capitals over the last decade. In Kanazawa, where four vehicles were submerged at two locations over ten years, Ishikawa Prefecture and Kanazawa City are implementing “air barriers”—inflatable devices that can be remotely operated to block traffic. Ishikawa Prefecture has approved a budget for five such installations, while Kanazawa City has already installed one.

Versions

  1. 2026-10-11 20:48 UTC Heavy rainfall and flooding risks in Japan
  2. 2026-10-06 21:17 UTC Heavy rainfall and flooding risks in Japan
  3. 2026-09-21 07:53 UTC Heavy rainfall and flooding in Japan
  4. 2026-09-12 23:17 UTC Heavy rainfall and flooding in Japan
  5. 2026-09-01 05:29 UTC Heavy rainfall and flooding in Japan

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