As many as 50 people are feared dead or missing and about 270 000 were prompted to evacuate their homes after severe flooding hit southern Japan's Kyushu island over the weekend. At least 10 locations in Kumamoto Prefecture recorded more than 410 mm (16 inches) of rain in 24 hours on Saturday, July 4, 2020-- including Kuma village's record-breaking 83.5 mm (3.3 inches) of rain in one hour-- while Kanoya city in Kagoshima prefecture had its highest ever rainfall of 109.5 mm (4.3 inches) in an hour on Monday, July 6.
The Japan Meteorological Agency (JMA) issued a warning on Saturday for an unprecedented downpour, urging residents on the island to take "maximum caution". About 270 000 people were advised to evacuate in four prefectures across the island.
In Kumamoto, wide swaths of Hitoyoshi were underwater. Ashikita and Kuma suffered severe damage after the Kuma River burst its banks in several locations, submerging several houses that prompted people to climb to their rooftops for safety.
"It was nothing but water as far as I could see," said 75-year-old Ashikita resident, Hirokazu Kosaki. Floodwaters washed away roads and bridges, cutting off many communities.
Heavy rains also triggered a huge landslide in the area at 02:40 UTC (11:40 LT). In an analysis by Dr. Dave Petley of The Landslide Blog, he pointed out that the disaster occurred on a "steep, forested mountain slope".
"When large landslides occur there is often a default view that human modification of the landscape, especially the removal of trees, is the cause (and often this is the case)," Petley explained.
"This landslide appears to demonstrate that, as all landslide researchers know, failures are a natural process that can occur on undisturbed forested slopes."
Kuma village recorded a record-breaking rainfall of 83.5 mm (3.3 inches) in an hour period. An elderly care home in the area was entirely flooded.
In Kagoshima, the city of Kanoya recorded its highest ever rainfall on Monday as up to 109.5 mm (4.3 inches) fell in one hour.
In a press conference, chief cabinet secretary Yoshihide Suga told reporters Monday that at least 21 have been confirmed dead, further 18 fatalities are yet to be verified, and 13 others remain missing.
"I offer my deepest condolences for those who have passed from the torrential rains," Suga stated.
40 000 members of the Japan Ground Self Defense Forces were involved in the massive search operations.
Look! Gentle Kuma River when our client visited then the same area after yesterday's horrific floods. The Meteorological Agency issued an alert for rain “never seen” before. There's something going wrong with our world #kumamotoprefecture #Hitoyoshi #globalwarmingisreal pic.twitter.com/AhQWr4t6bu— Si & Moo (@KyushuJourneys) July 6, 2020
Continuous heavy rain caused dramatic floods and landslides in Kyūshū Island (South of Japan).— Boris Weliachew (@Boris_sensei) July 4, 2020
15 deaths are already reported and the army has been mobilized to rescue inhabitants.#disaster #Flood #landslides #naturaldisaster #resilience #Japan #architecture #GlobalWarming pic.twitter.com/3wBd1AkIMw
災害列島 大雨コロナ— 菊田邦洋 (@palaiso9) July 4, 2020
Kyushu, Kumamoto Prefecture
Heavy rain, flood pic.twitter.com/9MTS4zHu4g
Japan's Fire and Disaster Management Agency reported that thousands of families have been isolated and 20 000 firefighters are currently on the ground attempting to reach them.
Authorities were using 28 helicopters, four planes, and two search ships to survey the area.
800 people had been rescued so far, 4 600 remain without electricity, while 7 000 were without water.
Suga warned of potential mudslides, noting that heavy rains saturated the ground in many of the affected areas.
A heavy rain warning remains in force for parts of both prefectures on Monday as more flooding is expected.
Featured image credit: Japan Ground Self Defense Forces