Nagoya took 104.5 millimetres of rain in a single hour, an all-time record that flooded roads and shut the rail network

A burst of extreme rainfall over central Japan overwhelmed drainage systems, rivers, and rail lines in one of the country’s largest cities earlier this month, setting a rainfall record that had stood for well over a century. The storm dumped more water on the city in a single hour than most monthly totals, forcing emergency evacuation orders for hundreds of thousands of residents and halting bullet-train service through the region. The scale of the downpour surprised even meteorologists tracking the system, since the previous record had survived a series of typhoons and seasonal rain bands over the decades.

Weather stations in the city have kept rainfall records since the late nineteenth century, giving forecasters an unusually long baseline for judging how extreme this particular storm actually was. The previous benchmark had stood since a historic rain event at the turn of the millennium, which made the new total significant not just for its raw intensity but for how decisively it broke a long-standing ceiling.

A Once-in-136-Years Hourly Total

The city’s main observation station recorded 104.5 millimetres of rain in a single hour on September 8, 2026, along with a 12-hour total of 213 millimetres, according to a detailed account of the event. That hourly figure was the highest ever recorded at the station, with data stretching back to 1890, and it broke the prior record of 97.0 millimetres set in September 2000 during a well-known historic rain disaster in the same region. Meteorologists identified a linear precipitation band, a narrow but intense corridor of repeatedly regenerating storm cells, parked over the western part of the surrounding prefecture and a neighboring region during the event.

Emergency Orders for More Than a Million Residents

As water levels rose along several rivers running through the city, local officials issued the country’s highest-level emergency safety measure for neighborhoods along three of them, citing rising water and the likelihood that flooding was already underway in some areas. That order, combined with a subsequent expansion to cover additional riverside communities, affected roughly 607,900 households and more than 1.1 million people spread across 14 city wards. National weather and infrastructure authorities separately issued a flood special warning for a major river system running through the area, the country’s highest classification, indicating flooding had occurred or was extremely likely.

Bullet Trains and Subways Grind to a Halt

The storm’s most visible disruption came on the rail network. Rainfall gauges between the city and a neighboring station exceeded the operating threshold used by the region’s high-speed rail operator, forcing a suspension of bullet-train service that rippled across wider sections of the line before trains gradually resumed hours later, though delays and cancellations continued into the evening. A conventional rail line running northeast from the city remained suspended for the rest of the day after roughly 305 metres of track was submerged. The city’s subway system shut down before resuming service progressively later that night, while municipal buses stayed off the road for the remainder of the day.

Flooded Streets, Stranded Drivers, and Closed Schools

Roads and low-lying buildings across the city flooded as the rain fell, and several vehicles were abandoned in flooded underpasses in one district after drivers escaped without injury. Local reporting counted four people injured across the wider prefecture during the event. With transit service disrupted for hours, the city opened temporary shelter facilities near several major stations for commuters who could not get home. City officials also announced that public elementary, junior-high, and high schools, along with special-needs schools and kindergartens, would stay closed the following day because of the storm’s continuing effects on roads and transportation.

A Storm System That Moved On, But Slowly

Emergency officials tracked the danger easing in stages rather than all at once. The city’s highest-level emergency measures along the three most affected rivers were downgraded to a lower evacuation-order level several hours after they were first issued, once water levels fell below the thresholds that had triggered the initial warnings. A separate flood special warning covering a major river system was reduced further, to a lower advisory level, in the early hours of the following morning, though authorities continued to caution that water levels were expected to stay elevated even after the most severe warnings were lifted.

Part of a Broader Pattern Across Japan This Season

The Nagoya storm arrived during a stretch of unusually active and severe weather across Japan, with record or near-record rainfall events reported in other parts of the country in the surrounding weeks. That clustering is consistent with the kind of intense, slow-moving rain bands that have become a recurring feature of the country’s late-summer weather pattern, in which narrow corridors of repeatedly regenerating thunderstorms can stall over the same area for hours, dropping far more rain locally than a typical moving storm system would produce over the same period.

This article was produced with AI assistance and edited by Morning Overview staff.

More from Morning Overview