Key Facts
• June 26: Intense rain due to an active cold front impacted Japan.
• Record rainfall observed at 22 locations nationwide, highest for June in history.
• Heavy rain and thunderstorms began in the evening, especially in Kanto and Tohoku regions.
• Gifu Prefecture’s Jizo Bridge suffered structural damage due to sudden water level rise.
• Urban flooding reported in Kansai, posing risks of accidents and damage.
• Chiba’s Kashiwa City implemented real-time water level monitoring in water pipes.
• ‘Air hammer phenomenon’ in sewers caused manhole covers to dislodge, creating hazards.
• Kashiwa City sewer capacity: 50 mm/hour, but recent rains reached 100-150 mm/hour.
• Officials aim to use monitoring systems as evacuation tools during extreme rainfall.
• Thunderstorm warnings remain for Hokkaido and mountainous areas in Kanto on June 27.
Summary
On June 26, Japan experienced record-breaking rainfall at 22 locations due to an active cold front and tropical airflows, causing severe thunderstorms and flooding. Gifu’s Jizo Bridge was damaged by sudden water surges, while urban flooding in Kansai highlighted risks of accidents. Kashiwa City in Chiba introduced real-time water level monitoring systems to mitigate flood impacts and address sewer-related hazards like the ‘air hammer phenomenon.’ With rainfall exceeding sewer capacity, officials emphasize these systems as vital evacuation tools. Thunderstorm warnings persist for Hokkaido and Kanto’s mountainous areas on June 27.
