Authorities in Hiroshima Prefecture and northern Kyushu Island have issued the highest alert for evacuation.
As part of this alert, which is not mandatory, about 1.4 million residents have been called to leave their homes immediately, according to public broadcaster NHK.
The Japan Meteorological Agency (JMA) has reported unprecedented levels of rain in this region.
Television footage shows people being rescued from lifeboats on flooded streets in Kurumi City (Fukuoka Prefecture) as a muddy current begins to flow in nearby Saga Prefecture.
A 59-year-old woman has died and two of her family are missing in Unzen (Nagasaki Prefecture, southwestern Japan) after two homes were buried in a landslide, according to a local official.
More than 150 soldiers, police and firefighters have been sent to help with relief operations
This official, Takumi Komasaki, told AFP.
They search for the missing, while keeping an eye out for possible landslides as the heavy rain continues
explained.
Heavy rain is expected to continue falling for several days over much of Japan.
Scientists say global climate change is causing the atmosphere to warm to contain more water, increasing the risks and intensity of intense precipitation.
Unprecedented levels of precipitation have been recorded
Yoshi Adachi, a JMA official, said at a press conference in Tokyo.
Extreme preparedness is needed even in areas where the risk of landslides and floods is not usually high
, according to him.
In early July, torrential rains caused a devastating mudslide in the resort of Atami, about 100 kilometers west of Tokyo, leaving 23 people dead and four missing.
In July 2020, record flooding in southwestern Japan left more than 80 dead or missing. Two years earlier, more than 200 people were killed in violent floods in the west of the country.
