The landslide engulfed the remote mountainous village of Lang Nu in Lao Cai Province, killing at least 22 people and leaving another 73 people still missing, multiple media reports said.
Yagi struck at the weekend bringing winds in excess of 149 kilometers (92 miles) per hour and a deluge of rain that has caused flooding not seen in decades. Officials have reported more than 140 killed in Vietnam alone.
Laos, Thailand and Myanmar have all also been hit by floods in the aftermath of the storm, with fatalities reported in both Thailand and Laos.
Nguyen Tran Van, 41, who has lived near the Red River in the Vietnamese capital Hanoi for 15 years, told AFP: "This was the worst flooding I have witnessed.
"I didn't think the water would rise as quick as it did. I moved because if the water had risen just a bit higher, it would have been very difficult for us to leave."
Worst floods since 2008
Hanoi has seen its worst floods since 2008 according to state media, with police, soldiers and volunteers deployed to help hundreds of residents along the banks of the swollen Red River to evacuate their homes in the early hours as water level levels rose rapidly.
A police official in Hanoi, refusing to be named, said officers were going on foot or by boat to check every house along the river.
"All residents must leave," he said. "We are bringing them to public buildings turned into temporary shelters or they can stay with relatives. There has been so much rain and the water is rising quickly."
On Tuesday images showed people stranded on rooftops and victims posted desperate pleas for help on social media, while 59,000 people were forced to evacuate their homes in Yen Bai Province.
A total of 16 provinces and cities remained at risk of landslides and flash floods Wednesday, although multiple state media reports said floodwaters had started to recede in mountainous areas.
The Vietnamese government said the toll from Yagi -- the strongest storm to hit northern Vietnam in 30 years -- had risen to 143 across the country, with 58 still missing.
It was not clear whether the figure included victims of Tuesday's landslide, where access remained difficult and internet cut off, reports said.
World Heritage site
In neighboring Laos, water levels on some rivers in Luang Prabang Province reached warning levels, reports said.
Houses and shops in the historic provincial capital -- a world heritage site -- were inundated, Lao Post reported.
State media said at least one person has been killed and images showed rescuers working in murky brown floodwaters.
In northern Thailand, four fatalities were reported, two in a landslide in Chiang Mai and two others in unclear circumstances in Chiang Rai.
The army was deployed to help and Prime Minister Paetongtarn Shinawatra said aid was on the way to around 9,000 flood-hit families.
In Myanmar, residents and local media said flooding knocked out power and telephone lines in the town of Tachileik, in eastern Shan state where further heavy rain was forecast.
Southeast Asia experiences annual monsoon rains, but man-made climate change is causing more intense weather patterns that can make destructive floods more likely.
Typhoons in the region are forming closer to the coast, intensifying more rapidly, and staying over land longer due to climate change, according to a study published in July.
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