Tokyo-Deep flood waters that left about 15 people dead and nine are missing on Sunday in the southern island of Kyushu.
The authorities have ordered more than 200,000 to move out and 10,000 defense groups, rescue helicopters, the coast guard, fire brigades are taking part in the operation.
At least 14 residents were presumed dead in the same flooded nursing home in Kuma village while the other was pulled from a landslide, an official said.
Heavy rainfall is prognosticated to continue overnight into Sunday.
Japan Prime Minister Shinzo Abe urged people to be on “maximum alert”.
Japan’s Meteorological Agency kept mudslide warnings in place across Kumamoto and said such rainfall had never been seen before in this region.
The rainfall that exceeds 100 millimeters per hour, the agency said.
The official residence of Kumamoto and Kagoshima has been the worst hit. More than 200,000 residents in Kumamoto were urged to shift due to pounding rains.
Footage shows a bridge over the Kuma river washed away, vending machine and car lay scattered on mud-coated streets.
As a consequence cut off power and communication lines, eventually delays search and rescue.