Historic rainfall triggers widespread flooding across Tokyo, Japan

Heavy rainfall triggered widespread flooding across the Kanto and Tohoku regions of Japan on Thursday evening, with parts of Tokyo receiving over 100 mm (4 inches) of rain within one hour.

Approximately 110 mm (4.33 inches) of rainfall was recorded in Tokyo’s Nerima Ward between 17:40 and 18:40 local time (LT) on Thursday. The same amount was recorded in Nakano Ward around 18:50 LT. Suginami recorded approximately 120 mm (4.72 inches) of rainfall by 19:00 LT, while Meguro Ward received 100 mm (3.94 inches) by that time.

A series of “record-breaking short-duration heavy rain” advisories were issued, mainly in the Kanto-Koshin region amid the historic rainfall. Although the peak of the heavy rainfall in Kanto-Koshin is subsiding, the risk of flooding and landslides remains a threat for low-lying areas.

The floods caused widespread damage, with one video on social media showing the leak through the roof of a railway station.

The flooding also disrupted road traffic, leaving vehicles at risk of becoming stranded. The Tokyo Fire Department received a report of a car stranded in a flooded underpass in the Yoyogi area of Shibuya Ward at 18:40 LT.

The driver was temporarily trapped inside the vehicle, but was able to evacuate independently and is safe, according to officials.

Heavy rainfall caused the Meguro River, which flows through Tokyo’s Shinagawa and Meguro wards, to reach the “flood risk water level,” the threshold at which local authorities are advised to issue evacuation orders.

The rising water level has placed both Shinagawa and Meguro wards at risk of flooding. The Tokyo Metropolitan Government and the Japan Meteorological Agency (JMA) have issued a Flood Risk Information Alert, urging residents to exercise extreme caution.

The agency is also warning of potential flooding in underground areas and is advising people to move to higher floors of buildings for safety.

The JMA has forecast up to 150 mm (6 inches) of rain in the 24 hours through 18:00 LT on Friday, July 11 in the Kanto region, which includes Tokyo, and 100 mm (4 inches) for the Koshin region of Yamanashi and Nagano prefectures.

Rishav Kothari

I am an Assistant Editor and Severe Weather & Science Journalist at The Watchers, specializing in real-time severe weather coverage, geophysical event reporting, and research-driven scientific analysis. You can reach me at rishav(at)watchers(.)news.

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