The Japan Meteorological Agency has issued a heavy rain emergency warning for parts of Gifu and Nagano prefectures in the central part of the country. The warning is the highest level of alert on the agency's scale.
The areas are experiencing rainfall that has not been seen in several decades. Agency officials say serious damage from flooding and landslides is likely.
They are urging people in the areas to evacuate to emergency shelters, or if it is too dangerous to travel, to seek safety in buildings with strong foundations.
If residents are unable to leave their homes, they are advised to stay on higher floors on the side of the buildings farthest from any nearby slopes.