Key Facts
• On July 1, 2025, Yamanashi Prefecture experienced torrential rain.
• Approximately 110 mm of rain fell near Yamanakako Village in one hour (2:30 PM).
• Fujiyoshida City and Oshino Village recorded about 100 mm of rain each (2:30 PM).
• The Japan Meteorological Agency issued a Record-Breaking Short-Term Heavy Rainfall Alert.
• Rain clouds developed due to warm, moist air, rising temperatures, and cold air aloft.
• Eastern Yamanashi and Fuji Five Lakes area face flood risks until evening.
• Record-Breaking Short-Term Heavy Rainfall Alerts are issued for rain exceeding 80 mm/hour.
• Such rainfall occurs only once every few years in affected regions.
• Residents are warned of landslides and rising river levels.
• Similar alerts were recently issued in Hokkaido for rainfall up to 120 mm/hour.
Summary
On July 1, 2025, Yamanashi Prefecture experienced record-breaking rainfall, with 110 mm falling near Yamanakako Village in one hour. Fujiyoshida City and Oshino Village also recorded 100 mm of rain each. The Japan Meteorological Agency issued a Record-Breaking Short-Term Heavy Rainfall Alert, warning of potential flooding and landslides in the eastern Yamanashi and Fuji Five Lakes areas. This rare weather event, caused by warm, moist air, rising temperatures, and cold air aloft, highlights the increasing frequency of extreme weather. Residents are urged to remain vigilant as similar alerts have been issued in other regions, such as Hokkaido.
