Tropical Storm Etau may have been a weak storm in terms of its winds, but it swamped some of the most populated areas of Japan with nearly two-feet of rain, yielding catastrophic flooding that has washed away houses and forced dramatic rescues.
There were no immediate reports of casualties, but rescue officials said they were overwhelmed by pleas for help. More than 30,000 people fled their homes, and hundreds more were stranded by the water.
The Fire and Disaster and Management Agency said 22 people have been injured by the storms over the past two days, including three elderly women who were seriously hurt when strong winds knocked them over.
As heavy rain pummeled Japan for a second straight day, the Kinugawa River broke through a flood berm, sending water gushing into the eastern half of Joso, a city of 60,000 people about 50 kilometers, or 30 miles, northeast of Tokyo.
Residents holding dogs wait for help, sitting on the roof of their house.
The Japan Meteorological Agency issued an emergency warning for heavy rainfall in an area north of Tokyo, where more than 20 inches of rain fell in just 24 hours. These warnings were later expanded to areas northeast of Tokyo as the torrential downpours shifted east, according to weather.com.
The Weather Channel reported that the city of Kanuma received 17.48 inches of rain in a 24-hour period, which was more than double the city's previous 24-hour precipitation record.
Aerial videos showed a wide swath of cityscape underwater, more than one story deep in some places. The rain came on the heels of Tropical Storm Etau, which caused flooding and landslides elsewhere Wednesday as it crossed central Japan, moving slowly.
Japanese broadcasters showed live video of rescuers being lowered from helicopters and clambering onto second-floor balconies to reach stranded residents.
In one dramatic scene, a rescuer descended four times from a military helicopter in a span of 20 minutes to lift up four people one by one, as a deluge of water swept around their home.
The Kinugawa River (left side) overflows during heavy rain in Joso, Ibaraki Prefecture,
By evening on Friday, local time, muddy water was still rising on a street heading to Joso City Hall, and police were blocking traffic in that direction.
"Looks like this place is going to be flooded soon," said Shogo Kobayashi, a 29-year-old resident of a nearby town who came to check on friends in Joso. "I'm getting scared."
Akira Motokawa, a city evacuation official, told public broadcaster NHK that rescuers have been unable to keep up with the volume of calls for help.
As of 7 p.m., authorities had rescued 70 of the 176 people who had requested help. Another 100 people were reported trapped on the second floor of a flooded supermarket, and 80 more in a nursing home.
More than 31,000 people in the affected 37-square kilometer (14-square mile) area sheltered at schools, community centers and other safer areas. Military troops were delivering food, blankets and water to about 780 people in several communities who were stranded but not seeking rescue.
Tokyo was drenched with rain, but the hardest-hit area was to the north in Ibaraki and Tochigi prefectures. One woman was missing hours after a landslide hit houses at the foot of a steep, wooded incline. High-speed "bullet" train service was partially suspended.