Heavy rain fell in many regions Thursday as a low pressure system made the atmosphere extremely unstable in northern and eastern parts of the country.
The Meteorological Agency issued a special warning to the Ishikari region in Hokkaido and urged caution against floods and mudslides.
According to radar analysis, rainfall of 100 mm per hour was registered in the Hokkaido cities of Eniwa and Chitose, while about 120 mm was registered in the city of Ishimaki and Higashimatsushima, Miyagi Prefecture.
The city of Sapporo set up a disaster countermeasures office on Wednesday morning, and issued an evacuation advisory to a total of 700,000 residents of 330,000 households due to fears of floods and mudslides.