Authorities on Monday urged millions to evacuate their homes after heavy rains unleashed floods and landslides in the Kyushu region and surrounding areas, leaving several residents missing.
Television footage from various communities in Kumamoto Prefecture showed houses, stores and vehicles submerged in about a meter of water.
Surging rivers swept away vehicles and damaged roads.
In the six hours to early Monday, more than 37 centimeters of rain fell in Kumamoto Prefecture's hardest-hit Tamana city, a record for the area, according to the Japan Meteorological Agency.
On Monday afternoon, the agency downgraded the special heavy rain warning — the level-5 highest alert — that it had issued for Kumamoto Prefecture to level-3 and level-2 alerts. The agency advised that people in the affected areas need to stay vigilant even though the alert level has been downgraded, as the heavy rain may have loosened the ground, making it easier for landslides to occur.
Evacuation advisories and warnings were issued to more than 3 million residents in the southwestern regions, according to the Fire and Disaster Management Agency. Some 384,000 residents, mostly in Kumamoto Prefecture, faced Japan's most serious evacuation warning, it said.
A father in the town of Kosa in the prefecture went missing early Monday after a landslide hit near his house while he stood outside his vehicle, a town official said. His wife and their two children were safe inside the car, the official said.
In Misato town, also in the prefecture, rescuers were trying to reach an elderly man trapped inside his house after it was struck by a landslide, the town's duty official said.
"Rain was so heavy that I couldn't see what's in front of me for four to five hours," Misato town official Kazuhiro Masunaga said.
Two people in Fukuoka city reportedly were swept away in a surging river Sunday and remained missing, national broadcaster NHK said.
Prime Minister Shigeru Ishiba has instructed a prompt assessment of damages and the mobilization of national government resources to carry out emergency disaster response measures.
Kyushu Railway Co., or JR Kyushu, had fully suspended operations on the Kyushu Shinkansen high-speed train line due to heavy rain but partially resumed operation on Monday afternoon.
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