Heavy rains in southwestern Japan have washed away homes, flooded hospitals, disrupted mobile phone services and cut off power and water for hundreds of households, officials said on Tuesday.

The unusually high level of rainfall in Kyushu, Japan’s southernmost main island, on Monday has left at least six people dead and three missing, Japan’s top government spokesman, Hirokazu Matsuno, said at a news conference.

Another official, Satoshi Sugimoto, the top forecaster at the Japan Meteorological Agency, on Monday called it “the heaviest rain ever experienced” in northern Kyushu.

Among those who died was a woman whose home was swept away by a landslide on Monday, according to NHK, Japan’s public broadcaster. Another victim was a man who had been trapped in his pickup truck in an inundated area.

In recent years, rains have taken hundreds of lives in Kyushu in part because its mountainous terrain is prone to landslides. Floods in Japan in July three years ago killed at least 86 people, mostly in Kyushu, and prompted the authorities to issue evacuation orders for millions of residents.

On Monday morning, the meteorological agency issued “special heavy rain” emergency warnings in parts of Kyushu. Later in the day, the agency downgraded the warnings. Local officials urged the region’s residents to evacuate to safety. By Tuesday, the rains had stopped, but officials warned residents to remain alert for landslides and floods.

“I’d like to ask people to pay attention to the weather information from municipalities,” Mr. Matsuno told reporters. “Please do not approach dangerous areas.”

Yoshiyuki Toyoguchi, an official with the land ministry, said at a news conference on Monday that the rains were so heavy that some of the region’s dams could overflow with another downpour.

The meteorological agency also warned residents throughout Japan that rainstorms would bring strong winds and lightning on Wednesday and Thursday.

Elsewhere in the world, unusually heavy rains have lashed India and parts of the United States, raising fears that climate change is driving an escalation in extreme weather events. Studies have shown that warmer weather has increased the chances of stronger storms.

In India, the current monsoon season has brought more than 10 times the average rainfall for this time of year in the northern state of Himachal Pradesh. The heavy rains washed away bridges and buildings last weekend and killed 23 people.

Flash floods also struck New York State on Sunday, inundating roads and causing at least one death. Vermont’s river valleys and mountain towns were also ravaged by rains on Monday.

Governor Kathy Hochul of New York called the extreme weather emergencies that continued in her state “our new normal.” President Biden declared a state of emergency in Vermont early Tuesday.