At least five people are dead, one is in cardiac arrest, and over 10,000 were stranded far from home after a succession of powerful rainfall systems swept through Japan's Chiba Prefecture on August 13 and 14, producing the area's highest 24-hour precipitation total since records began half a century ago.
Three separate linear precipitation bands — narrow corridors of concentrated, slow-moving convective rainfall — formed over the prefecture between the evening of August 13 and the early hours of August 14. Meteorological authorities issued 25 emergency weather alerts over the course of the event.
367 Millimeters In 24 Hours: Chiba's Rainfall Record Since 1976 Falls
In Chiba City's Chuo Ward, 24-hour rainfall totaled 367.0 millimeters, eclipsing the previous all-time high of 309.0 millimeters and setting a new benchmark since the Japan Meteorological Agency began maintaining records for the city in 1976. Over a shorter window, 12-hour precipitation in the same ward hit 348.0 millimeters — itself an all-time observed high.
千葉駅えぐすぎて草 pic.twitter.com/XFcUgZrS1v
— 人生の負け組 (@pEmQc5ivRI82636)August 13, 2026
こんな状態でも駅まで乗客を届ける千葉市のバス
— Masa (@masanews3)August 13, 2026
神すぎる🙏🦁#ゲリラ豪雨pic.twitter.com/PVC7coEJj7
At the height of the emergency, the agency issued its maximum Level 5 heavy rain warning across 22 municipalities, among them Chiba City, Ichikawa, Funabashi and Ichihara. Six of those cities additionally received Level 5 landslide warnings, the most severe designation on the agency's scale. All Level 5 alerts were stepped down by 5:15 a.m. on August 14, and the remaining Level 4 heavy rain danger warnings were reduced to Level 2 advisories by 10:33 a.m. Even so, Level 4 landslide danger warnings remained active for Chiba City, Ichihara, Mobara and Oamishirasato as of midday August 14.
水没して車たち
— パサヒト𓆉動植物 (@pasahito)August 13, 2026
天井まで水没しても通電してるハザードが悲しすぎる#線状降水帯#稲毛区#千葉市#冠水#浸水#大雨pic.twitter.com/ukNMSvyhqx
Drivers Trapped In Rising Water, Deaths On Flooded Roads
Most casualties occurred on deeply submerged roads across the prefecture. A man found on a flooded road in Ichikawa was confirmed dead. In Yachiyo, a man discovered unresponsive on a waterlogged road also died. In Sakura, a 66-year-old woman became trapped inside her vehicle as floodwaters rose around it and later died. A fourth person — a woman in her 70s — was pulled from a car she could not escape in Kashiwa, but remained in a state of cardiopulmonary arrest as of midday August 14.
今の蘇我駅、さすがに大変すぎる…🌧️
— Ren (蓮) (@TiwariRajend)August 13, 2026
「座ったらダメ」と思って4時間立ちっぱなしだったけど、もう限界。
電車の中のほうが空いてるから、そこで夜を明かすという判断に。
こんな状況になったら、あなたならどうする？#千葉#大雨pic.twitter.com/NvnB0b3Gsd
Current visuals from Chiba City (千葉市), Chiba Prefecture, Japan.
— Weather Monitor (@WeatherMonitors)August 13, 2026
Level 5 Torrential Rain Warning just issued for Chiba. pic.twitter.com/mFKHzrZ2qn
The Fire and Disaster Management Agency's report released at 11 a.m. on August 14 confirmed four deaths directly attributed to the flooding: one each in Ichikawa and Yachiyo, and two in Sakura. Two additional deaths in Chiba City were still being investigated for a possible link to the heavy rain. Midday reports put the overall toll at five, with the figures expected to change as damage assessments continue.
Property damage is still being tallied. As of 11 a.m., at least one building had been partially destroyed, 45 homes flooded above floor level, and 39 below floor level. In Oamishirasato, extensive flooding centered on the area around Oami Station submerged numerous vehicles and residences. The full picture remains unclear.
Narita Airport And Soga Station: Over 10,000 Stranded Overnight
The flooding brought transportation across the prefecture to a standstill. Narita International Airport — a critical hub for routes linking Japan with Taiwan, South Korea and Southeast Asia — and JR Soga Station together saw more than 10,000 people unable to make it home as train and bus services collapsed. JR East's Narita Express remained suspended until around 3 p.m. on August 14, with further delays expected across Chiba's rail network for the rest of the day.
Evacuation orders covered a vast area. As of 11 a.m. on August 14, the Fire and Disaster Management Agency counted 95,289 people in Chiba under emergency safety confirmation orders and 102,585 under formal evacuation instructions.
Forecasters cautioned that danger persists. Soil across Chiba remains heavily saturated after the record deluge, and atmospheric conditions across the Kanto region — which includes Tokyo — were expected to stay highly unstable through the early morning of August 15, prolonging the threat of landslides even as the worst of the rain passes.
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