Japan Confronts Typhoon Dujuan
Japan is beginning the difficult transition from disaster response to recovery after Typhoon Dujuan brought record-breaking rainfall, flooding and landslides across the country’s eastern regions. The storm moved away from Japan on Tuesday, September 22, but its most serious consequences remain on the ground, particularly across the Kanto region surrounding Tokyo. At least four people have been reported dead and six remain missing, according to reports citing Japanese authorities, while roads, railways, utilities and communities continue to contend with the aftermath. (Reuters)
Dujuan, designated Typhoon No. 25 by Japan’s Meteorological Agency, approached the country after forming in the Mariana Islands on September 16 and intensified before reaching the waters near Japan. On September 21, the storm approached the Izu Islands and Kanto region with strong winds and torrential rain, bringing dangerous conditions to one of the country’s most densely populated and economically important areas. Japan’s Ministry of Land, Infrastructure, Transport and Tourism reported that some locations in the Kanto-Koshin region recorded their highest 24-hour rainfall totals on record, while cumulative rainfall from September 19 through 21 exceeded 800 millimeters in parts of the Izu Islands, 500 millimeters in Shizuoka Prefecture and 450 millimeters in Chiba Prefecture. (MLITT)
When Rain Becomes the Disaster
The scale of the rainfall is central to understanding the damage. On Oshima in the Izu Islands, Japan’s official meteorological records show 686.5 millimeters of precipitation in 24 hours on September 21, while the island recorded more than 800 millimeters over a longer period. Chiba also experienced exceptional rainfall, with some locations exceeding 300 millimeters in 24 hours. The combination of saturated ground, swollen rivers and intense additional rainfall created conditions in which flooding and landslides could develop rapidly. (JMA Data Portal)
Japan’s geography makes the consequences particularly complex. Mountains and steep terrain can accelerate runoff, while densely developed coastal and urban areas concentrate homes, roads, railways and other infrastructure in relatively limited spaces. When rainfall exceeds the capacity of drainage systems or destabilizes already saturated slopes, the consequences can move quickly from a weather event to an infrastructure emergency. In this case, the greatest danger did not simply come from wind; water and unstable ground became the defining threats.
The Japan Meteorological Agency issued its highest-level landslide special warning for Oshima during the storm, while Level 4 warnings covering landslides, heavy rain and flooding were issued across portions of the Tokai and Kanto-Koshin regions. Even after the typhoon moved offshore, authorities continued warning that saturated ground and elevated river levels could produce delayed hazards. The official government assessment on September 22 still listed Level 4 landslide warnings in parts of Chiba and Kanagawa. (MLITT)
The Human Cost
The human toll has continued to become clearer as emergency crews gain access to affected areas. Japan’s Ministry of Land, Infrastructure, Transport and Tourism reported one death and four missing people in Kanagawa Prefecture as of its 9:00 a.m. September 22 assessment, in addition to another death in Miyazaki Prefecture. Separate reporting based on NHK information put the wider toll at four dead and six missing as search-and-rescue operations continued in Kanagawa and Chiba. (MLITT)
The landslides around Kanagawa illustrate why the end of the storm does not mean the end of the emergency. Rescue teams have been searching areas around the Miura Peninsula after landslides struck homes, while debris and mud have obstructed access. In communities affected by slope failures, the danger can persist after the rain stops because saturated earth can continue shifting. Recovery therefore requires not only clearing roads and restoring utilities, but determining which areas remain unsafe for residents and responders.
Across the wider affected area, evacuation warnings and advisories reached well beyond the locations that ultimately suffered the most visible damage. Reports on Monday indicated that more than 1.6 million people in and around Tokyo were urged to evacuate or take protective action, while Reuters imagery and reporting described the broader affected population as approaching 1.9 million under evacuation-related measures. The numbers demonstrate the scale of Japan’s precautionary response to a storm moving through a heavily populated region. (Al Jazeera)
A City Region Interrupted
The disruption extended far beyond individual neighborhoods. Airports, railways, highways and bus networks were all affected as authorities dealt with flooding, debris, dangerous rainfall levels and transportation restrictions. Japan’s transport ministry reported 457 flight cancellations on September 21, including 152 by Japan Airlines and 150 by All Nippon Airways, with additional cancellations scheduled for September 22. Fourteen conventional rail lines operated by seven companies were still suspended in the government’s morning assessment, while road closures affected highways and local routes across several prefectures. (MLITT)
The disruption is particularly significant because the Kanto region is not simply another geographic area within Japan. It contains Tokyo, one of the world’s largest metropolitan economies, together with an enormous network of industrial, commercial, transportation and residential infrastructure. Interruptions to movement in the region can therefore affect commuters, businesses, logistics operators and travelers well beyond the neighborhoods directly touched by floodwater.
The storm also collided with Japan’s holiday calendar. Dujuan arrived during Silver Week, a period when domestic travel typically increases, and it disrupted sporting, cultural and entertainment activities. The Tokyo Game Show was forced to close early on its final day, while events in Chiba were canceled or disrupted as authorities prioritized safety. (Al Jazeera)
Infrastructure Under Pressure
The physical damage reveals another dimension of the storm. Japan’s transport ministry reported landslide-related closures on major expressways, including portions of the Tateyama Expressway, Futtsu-Tateyama Road and the Ken-O Expressway. Roads were also closed because of flooding, fallen trees and slope failures, while a number of prefectural roads remained inaccessible. One isolated community in Kisarazu, Chiba Prefecture, was reported to contain four households and 10 people after a slope collapse restricted access. (MLITT)
Water infrastructure was affected as well. The government’s September 22 assessment recorded water outages affecting communities in Chiba Prefecture, including parts of Chiba City, Kimitsu and Minamiboso. Approximately 750 households were without water at the time of that assessment, with emergency water supplies being arranged or provided. These disruptions illustrate how the consequences of extreme rainfall move through interconnected systems: roads affect access, access affects utility repairs, and utility failures affect households long after the storm itself has passed. (MLITT)
Electricity was another major concern. Tokyo Electric Power Company reported approximately 45,000 households without power in the affected region, according to Reuters. Restoring electricity safely can take time when utility crews must work around flooded roads, fallen trees, unstable slopes and damaged infrastructure. (Reuters)
Japan’s Disaster Response System
Japan has extensive experience with earthquakes, typhoons, floods and landslides, and Dujuan activated a substantial government response. The transport ministry established emergency coordination with dozens of local governments, while technical disaster-response teams were deployed to affected communities. As of the September 22 morning assessment, the ministry had personnel working in Chiba, Tokyo and other affected areas, with drainage-pump vehicles deployed to assist communities dealing with accumulated water. (MLITT)
That institutional preparation matters because disaster management in Japan is built around layered responsibilities. National agencies provide meteorological information, infrastructure support and specialized resources, while prefectural and municipal governments manage local warnings, evacuation decisions and community response. The system is designed to move resources toward the areas facing the greatest immediate risk while maintaining national transportation and communications networks.
But preparation does not eliminate vulnerability. A sophisticated disaster-response system can reduce exposure and speed recovery without preventing extreme rainfall from overwhelming individual communities. Dujuan demonstrates the continuing challenge for a country that has invested heavily in resilience while facing increasingly disruptive weather events.
The Geography of a Changing Climate
It would be too simple to attribute any individual storm solely to climate change. Tropical cyclones naturally vary in strength, track and rainfall, and establishing a climate connection requires analysis beyond the occurrence of a single event. What can be documented is that Japan, like many countries, is confronting a growing policy and infrastructure question around extreme precipitation, flooding and disaster resilience.
The immediate numbers from Dujuan provide a useful illustration of that challenge. Rainfall totals in several areas broke historical records, including monthly or observational records, while the storm produced landslides and flooding across heavily developed parts of eastern Japan. Japan’s government will now have to address both the immediate physical repairs and the longer-term question of whether infrastructure, land-use planning, drainage systems and emergency protocols are adequately calibrated for events of this intensity. (MLITT)
The question is not simply whether another typhoon will arrive. It is how much rainfall a city, highway, railway, river system or hillside can absorb before its assumptions about normal conditions stop working. That is ultimately an engineering and planning question as much as it is a meteorological one.
After the Storm
By Tuesday morning, Dujuan was moving northeast over the Pacific and away from Japan. The immediate threat from the storm’s strongest winds was therefore diminishing, but officials continued to warn about landslides, swollen waterways and unstable ground. Japan’s Weathernews reported that the typhoon remained strong as it moved east of the country, while rainfall-related hazards persisted across Kanto and the Izu Islands. (ウェザーニュース)
The next phase will be measured less by wind speed than by recovery. Roads must reopen, electricity and water must be restored, rail networks must return to normal, damaged homes must be assessed and missing people must be located. For families who have lost homes or loved ones, the storm will not end when the weather clears.
Japan has spent decades developing one of the world’s most sophisticated approaches to living with natural disasters. Typhoon Dujuan is another reminder that resilience is not a finished condition. It is an ongoing negotiation between geography, infrastructure, technology, government and the communities that depend on all four.
For Japan, the blue sky after Dujuan is only the beginning of the next task. The storm has moved offshore. The work of understanding what it left behind has begun.
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