Record rainfall exceeding 36 cm in 24 hours struck parts of Chiba prefecture on or before August 13, 2026, prompting Japan's highest-level heavy rain warning and causing at least four deaths from flooding. Power outages affected nearly 25,000 households, thousands were stranded at stations and airports, and the Japan Meteorological Agency later downgraded alerts for multiple municipalities. Coverage of the event derives exclusively from left-center sources.