August 2026 Chiba Heavy Rainfall

Fatalities

13persons

Source: 01 被害情報（令和８年８月千葉豪雨）第１４報.pdf

Cardiac Arrests

2persons

Source: Jiji.com (August 14, 2026)

Missing

1persons

Source: 01 被害情報（令和８年８月千葉豪雨）第１４報.pdf

Injuries

44persons

Source: 01 被害情報（令和８年８月千葉豪雨）第１４報.pdf

Homes Flooded Above Floor Level

1,206structures

Source: 01 被害情報（令和８年８月千葉豪雨）第１４報.pdf

Homes Flooded Below Floor Level

1,489structures

Source: 01 被害情報（令和８年８月千葉豪雨）第１４報.pdf

Rivers That Overflowed or Exceeded Flood Levels

According to Ministry of Land, Infrastructure, Transport and Tourism (MLIT) documents, no flood damage from nationally managed rivers was reported (as of August 15–16). Inundation damage was confirmed along 5 prefecturely managed rivers, though individual river names could not be identified from publicly released materials. The primary driver of damage appears to have been urban (inland) flooding caused by drainage systems being overwhelmed — including inundation of roads and underpasses — rather than direct river overflows.

Source: Fukushima no Bosai HIH (compiled from MLIT materials) / MLIT Damage Situation Report (5th Release)

Maximum 24-Hour Rainfall

364mm

Source: Japan Meteorological Association tenki.jp (August 14, 2026)

Rainfall Records

The AMeDAS Chiba station (Chuo Ward, Chiba City) recorded 115.0 mm in 1 hour ending at 18:48, 188.5 mm over 3 hours, and 293.0 mm over 6 hours — all of which far surpassed records dating back to observations beginning in 1966. All-time records were also broken in Sakura City and Tateyama City. Beginning near Kashiwa City and Abiko City, Extraordinary Heavy Rain Alerts were issued successively for Ichihara City, Chiba City, Sakura City, Yachiyo City, Inzai City, Yotsukaido City, Funabashi City, and Shiroi City. At 19:30 on the 13th, a Special Heavy Rain Warning was issued; at 20:58, a flash report on the formation of a linear precipitation band (senjo kosuitai) was issued; and at 21:55, a Special Landslide Disaster Warning was issued.

Source: WeatherNews / NIED Water and Sediment Disaster Research Division

Landslides

A confirmed total number of landslides and debris flows has not been established. A Level 5 Special Landslide Disaster Warning was issued for 6 cities including Chiba City and Ichihara City, and cliff collapses were reported at multiple locations across the affected area; however, the total count remains unconfirmed.

Source: Rescue Now, Inc.

Evacuation Orders

200,000households

Source: Rescue Now, Inc.

Road Closures

4locations

Source: 01 被害情報（令和８年８月千葉豪雨）第１４報.pdf