Record rainfall brings landslides and infrastructure disruption to Yakushima, Japan

Record rainfall associated with Typhoon No. 24 and an autumn-rain front affected Yakushima Town, Kagoshima Prefecture, from September 4 to September 5, 2026. Rainfall broke the all-time September record at Onoaida, reaching 490.5 mm (19.31 inches) by JST. The Japan Meteorological Agency (JMA) issued a Level 5 Landslide Disaster Special Warning at before replacing it with a Level 4 warning at JST, while authorities reported landslides, water outages affecting as many as 289 households, and large amounts of driftwood at Miyanoura Port. Onoaida recorded 403 mm (15.87 inches) of rain in 12 hours and 479.5 mm (18.88 inches) in 24 hours ending at JST on September 5, according to the Japan Meteorological Agency. Both totals established new all-time records for the station. JMA’s other station on Yakushima recorded 356 mm (14.02 inches) in 12 hours and 422 mm (16.61 inches) in 24 hours, setting September records. All-time rainfall records were also established at Nakatane on neighboring Tanegashima. The 24-hour total at Onoaida subsequently reached 490.5 mm (19.31 inches) by JST, according to MBC South Japan Broadcasting. Rainfall since the beginning of the episode had reached approximately 558 mm (21.97 inches), nearly twice the station’s normal rainfall for the entire month of September. Rainfall intensified during the evening of September 4, when radar analysis showed approximately 120 mm (4.72 inches) falling near Yakushima Town during the hour ending at JST. JMA issued record short-duration heavy-rain information in response. Successive linear precipitation zones developed over the Tanegashima–Yakushima area during the night and early morning, rapidly increasing the risk of flooding and landslides. The heavy rainfall occurred as Typhoon No. 24 and an autumn-rain front affected southern Japan. JMA issued a Level 5 Landslide Disaster Special Warning for Yakushima Town at JST on September 5, saying unprecedented rainfall was occurring and that the probability of a landslide disaster having already occurred was extremely high. The special warning corresponded to Alert Level 5 meteorological information and called for immediate action to protect life. It did not mean that Yakushima Town had issued a municipal Level 5 Emergency Safety Measure. At JST, JMA replaced the special warning with a Level 4 Landslide Disaster Danger Warning. Yakushima Town’s evacuation action remained a separate Level 4 Evacuation Order. Kagoshima Prefecture’s JST situation report listed the evacuation order as covering 3 574 households and 6 228 people. The order had been issued at JST on September 4, and the prefectural report did not list a cancellation time. Eleven evacuation shelters were listed as operating in Yakushima Town, although the prefecture did not provide a corresponding number of people staying in them. Heavy rain damaged part of the water-intake system serving the Nagamine district, cutting water service to as many as 289 households.