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6 clusters · 14 sources · 50 days · First seen · Last updated

Heavy rainfall and flooding risks in Japan

Overview

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. The Tokyo Disaster Prevention handbook suggests using a vehicle’s headrest to break glass if a hammer is unavailable. In late August 2026, the JAF Fukui branch reported approximately 211 rescue requests for submerged vehicles, roughly triple its usual volume.

Authorities have increasingly focused on the danger of underpasses. Following a fatal accident in Kashima, Iwaki City, the Ministry of Land, Infrastructure, Transport and Tourism released guidelines requiring road managers to categorize underpasses into four risk levels and implement measures like remote barriers and electronic signage. In Kyoto, residents in areas like Ukyo-ku have begun using digital platforms to warn neighbors against entering underpasses during 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.

Entities

Ministry of Land, Infrastructure, Transport and Tourism · JAF · Fukui Prefecture · Kyoto · Kanazawa

Timeline

  1. [INTERNATIONAL] 2 sources
    Japan underpass flooding: 134 vehicles submerged in 10 years

    A survey shows 134 vehicles have been submerged in underpasses across 33 Japanese prefectural capitals over the last decade, prompting cities like Kanazawa to install remote-controlled air barriers.

  2. [POLITICS] 3 sources
    Japan issues new safety guidelines for underpass flooding

    Japan's Ministry of Land, Infrastructure, Transport and Tourism issued new safety guidelines for underpasses following fatal flooding accidents, mandating risk assessments and traffic restrictions.

  3. [INTERNATIONAL] 3 sources
    Heavy rain causes vehicle flooding risks in Japan

    Heavy rains in Japan, specifically in Fukui, have led to increased vehicle flooding. JAF advises drivers to turn back if water reaches 15cm to avoid risks like hidden manholes or engine failure.

  4. [INTERNATIONAL] 2 sources
    Japan authorities issue flood safety guidance for submerged vehicles

    Japanese authorities are urging drivers to carry emergency escape hammers and avoid flooded roads to prevent being trapped in submerged vehicles during heavy rainfall.

  5. [INTERNATIONAL] 3 sources
    Japan: Rising heavy rain frequency prompts calls for better drainage and insurance awareness

    A survey shows 65% of Japanese respondents notice an increase in heavy rain, leading to calls for better drainage infrastructure and heightened awareness of vehicle insurance and loan risks during floods.

  6. [INTERNATIONAL] 2 sources
    Japan rainfall warnings: Vehicle flooding risks and safety advice

    Following record rainfall in Chiba, experts warn against driving through flooded roads, noting that even SUVs can stall in deep water and face significant risks of entrapment.

Sources

bestcarweb.jp · financial-field.com · fnn.jp · fukuishimbun.co.jp · hokkoku.co.jp · hta.or.jp · huffingtonpost.jp · iwaki-minpo.co.jp · jugem.jp · kyoto-np.co.jp · prtimes.jp · sakigake.jp · the-miyanichi.co.jp · tokyo-sports.co.jp

This summary has been updated 4 times: see revision history