Typhoon No. 4 made landfall near Sasebo, Nagasaki Prefecture shortly before 6 a.m. on July 5, dumping record levels of heavy rain in Kyushu and Shikoku regions.
The Japan Meteorological Agency is calling for heightened vigilance against possible landslides from western Japan to the Pacific coast of eastern Japan until July 6.
The agency reported in the early hours of July 5 that linear rain bands, called “senjo kosuitai”, were rapidly producing torrential rains in western parts of Kochi prefecture.
Susaki in the prefecture received a record 208 millimeters of rainfall over a three-hour period until shortly after 1 a.m.
The JMA also reported that 120mm or more of rain fell during the hour the typhoon made landfall near Unzen in Nagasaki Prefecture, Arao in Kumamoto Prefecture and Omuta in Fukuoka Prefecture. The agency urged residents to prepare for potentially heavier rains.
Omuta set an hourly rainfall record for July at 85mm.
As of 7:30 a.m., evacuation orders had been issued to 90,610 people from 44,804 households in two cities in Ehime and Kagoshima prefectures, according to the Fire and Disaster Management Agency.
The agency also confirmed on July 5 that eight houses in Kochi were flooded underground.
The typhoon weakened into an extratropical cyclone at 9 a.m. and is expected to move from western Japan to the Pacific coast of eastern Japan.
Predicted rainfall for the 24-hour period until noon on July 6 is up to 200 mm in Tokai and Shikoku region, 150 mm in Kanto-Koshin and Kinki regions and 100 mm in southern Kyushu.
Heavy rain is also forecast for parts of northern Japan as weather conditions become unstable due to warm, moist air blowing around the Pacific High System.
Hokkaido and the Tohoku region can expect up to 80mm of precipitation over the 24-hour period until noon on July 6.