Mount Fuji landslide follows record Nagoya rain as Japan flooding injures 41

Central Japan is dealing with widespread disruption from an extreme rainfall episode that produced a record 104.5 millimetres of rain in one hour in Nagoya, injured 41 people across Aichi and Gifu prefectures and triggered separate landslides in mountainous Shizuoka. One landslide struck a major Mount Fuji climbing access point and buried three vehicles without reported injuries, while another in Kawanehon killed a worker who had initially been found unconscious.

The Japan Meteorological Agency’s observations show exceptional multi-day rainfall across parts of Shizuoka, including more than 350 mm at Utoogi and more than 300 mm at Ikawa during the latest 72-hour measurement window. Authorities have kept road restrictions in place around affected mountain areas, while the Fuji Subaru Line was closed because of heavy rain and climbing-season access was already approaching its scheduled September shutdown.

The flooding has also reached preparations for the Asian Games, which open in Nagoya on September 19. Around 400 athletes and staff were temporarily moved to higher ground and approximately 3,500 residents used emergency shelters, although Mayor Ichiro Hirosawa says organisers currently see no reason to delay the Games and no major damage has been identified across competition venues.

What happened at the Mount Fuji climbing access point during the heavy rain?

A landslide struck the area around the fifth station serving Mount Fuji’s Fujinomiya trail, one of the principal starting points used by climbers attempting the mountain. Three vehicles were covered by debris, but authorities had not reported deaths or injuries from that specific incident in the latest information.

The landslide followed intense overnight rainfall in Shizuoka’s mountainous areas, where soil saturation increases the likelihood that steep slopes will fail even after rainfall temporarily weakens. Mount Fuji’s access roads are particularly exposed because they climb through steep volcanic terrain in which runoff and loose material can move rapidly across roadways.

Two climbers were separately found unconscious on Mount Fuji and a mountain-rescue team was dispatched, but police had not connected those cases to the landslide. Keeping those incidents separate is important because proximity in time does not establish a shared cause.

How exceptional was the rainfall recorded around Nagoya and Shizuoka?

Nagoya recorded 104.5 mm in a single hour on Tuesday evening, a record intensity that overwhelmed transport networks and urban drainage in parts of the city. Roads and homes flooded, public transport was interrupted and commuters formed long queues after services were suspended or delayed.

Shizuoka experienced a different but equally serious pattern involving heavy cumulative rainfall across mountainous locations. JMA data showed 72-hour totals of 353 mm at Utoogi, 307.5 mm at Ikawa and 250 mm at Shiraito by the morning of September 9, leaving slopes saturated over a wide area.

These two rainfall profiles produce different hazards. Exceptional hourly intensity creates flash flooding quickly in cities, whereas prolonged accumulation penetrates hillsides and can produce landslides hours after the strongest rain has passed.

Why were hundreds of Asian Games athletes temporarily evacuated?

Around 400 athletes, officials and staff staying in temporary accommodation were moved to higher ground as flooding intensified. Organisers took the precaution because heavy rain was affecting roads and surrounding areas, even though no athlete injuries were reported and participants were later allowed to return.

Several competition facilities experienced leaking roofs, but officials said they had not found structural damage serious enough to threaten the event. Nagoya’s mayor therefore maintained that the Games, scheduled from September 19 through October 4, should proceed as planned.

The event is expected to bring more than 11,000 athletes from 45 countries and regions, making disruption to transport and accommodation as important as physical damage to stadiums. The next several days will give organisers time to inspect facilities and infrastructure before large numbers of additional participants arrive.

Why can landslides continue after the most intense rainfall ends?

Heavy rain fills pores and cracks in soil and rock with water, increasing weight while reducing the friction holding slopes together. Once the ground reaches a critical saturation point, a slope can fail even after rainfall intensity has fallen because water pressure continues redistributing underground.

The fatal Kawanehon incident demonstrates that the risk is not confined to Mount Fuji. Mountain roads, construction sites and rural communities across Shizuoka may remain vulnerable until water levels decline and authorities confirm unstable slopes are secure.

This delayed hazard is why reopening roads too quickly can be dangerous. Engineers may need to inspect retaining structures, drainage systems and exposed slopes before allowing normal traffic, particularly where rainfall totals have accumulated over several days.

What are the key takeaways from central Japan’s September 9 extreme rainfall?

• Nagoya recorded a record 104.5 mm of rainfall in a single hour during the severe weather episode.
• Flooding across Aichi and Gifu injured 41 people and disrupted road and public-transport operations.
• A landslide near a major Mount Fuji climbing access point buried three vehicles, but no injuries were reported from that incident.
• A separate landslide in Kawanehon, Shizuoka, killed a worker.
• JMA data show more than 300 mm of rainfall over 72 hours at some Shizuoka monitoring locations.
• Around 400 Asian Games athletes and officials were temporarily evacuated, while approximately 3,500 residents used emergency shelters in Nagoya.
• Officials say the Asian Games remain scheduled to begin September 19 despite localised flooding and leaks at some facilities.

Will Japan’s biggest problem now come from the rain itself or from what the saturated ground does next?

For urban areas around Nagoya, the immediate challenge is restoring roads, public transport and flooded buildings after an unusually intense short-duration downpour. In Shizuoka’s mountains, however, the danger can persist much longer because saturated slopes may remain unstable after skies begin clearing.

The Mount Fuji incident illustrates how a weather emergency can quickly become a transport and tourism problem even without casualties at the specific landslide site. Tens of thousands of climbers and visitors rely on a limited network of mountain roads and access points, leaving few alternatives when one route becomes unsafe.

Japan’s next phase is therefore about inspection as much as forecasting. The rainfall totals have already been recorded, but the full consequence will depend on whether damaged slopes, roads and drainage systems remain stable as authorities begin reopening affected areas.