Japan's late-June Baiu floods kill at least one and leave five missing as Mekkhala and Higos worsen the seasonal front

Summary

Tropical storms Mekkhala and Higos interacted with Japan's Baiu seasonal rain front in late June 2026, producing extreme rainfall across Kyushu, the Kinki, Tokai, and Hokuriku regions. At least one person, a man in his 70s, died in a landslide that collapsed a house in Yamaguchi prefecture. Five people were reported missing: four workers at a construction site in Wajima, Ishikawa, where a mudslide struck a tunnel-repair operation following the January 2024 Noto Peninsula earthquake, and one more in Wajima from flooding. Sixteen rivers in Ishikawa breached their banks by late on June 27. About 6,500 homes lost power across affected prefectures. The Japan Meteorological Agency forecast 250 mm of additional rain for the Tokai region in a single 24-hour window, and 200 mm for Kanto-Koshin.

The split

Japanese media and the JMA emphasised the compound nature of the emergency: Wajima was already deep in earthquake reconstruction, and the flood-triggered landslide at an active construction site added a layer of complexity to search and rescue that standard Baiu response plans do not cover. Overseas disaster-tracking organisations focused on the tropical-storm-to-frontal interaction mechanism, noting that the simultaneous presence of Mekkhala and Higos east and west of the archipelago squeezed exceptional moisture into the Baiu front. Climate scientists who track East Asian monsoon intensification pointed to the pattern as consistent with projections showing increased frequency of extreme rainfall events during the Baiu season under continued warming.

By the numbers

• At least 1 death (Yamaguchi landslide)
• 5 missing (4 in Wajima construction site mudslide, 1 in Wajima flooding)
• 16 rivers in Ishikawa prefecture breached their banks
• About 6,500 homes without power
• 250 mm forecast rainfall for Tokai region in 24 hours
• 2 tropical storms simultaneously active: Mekkhala and Higos

Why it matters

Japan's East Asia Monsoon Baiu season typically accounts for the country's most destructive flood and landslide events outside of typhoon season. The June 2026 episode illustrates an intensifying pattern where tropical systems that would historically move away from the archipelago are instead merging with or amplifying the stationary Baiu front, producing rainfall extremes above what regional flood infrastructure was designed to handle. Wajima's situation, still rebuilding from the 2024 Noto earthquake and now hit by Baiu flooding, is a case study in compound disaster vulnerability that Japan's disaster management agencies are studying as they revise multi-hazard response plans.

What to watch

• Final confirmed death and missing-person tolls from Wajima and Yamaguchi
• Whether the Baiu season continues above-normal through its expected end in mid-July
• Progress of Wajima's earthquake reconstruction following the flood damage setback
• JMA post-season attribution of the Mekkhala-Higos-Baiu interaction to seasonal climate anomalies