Over 200 people have now died while millions of residents across India, Nepal, Bangladesh and Pakistan have been affected and hundreds of thousands displaced by heavy rains.
Heavy monsoon rains across South Asia claimed more lives on Wednesday, with the death toll passing 200 as authorities tried to reach stranded villagers cut off by surging floodwaters.
The annual deluge is crucial to replenishing water supplies in the impoverished region, but the rains from June to September often turn deadly.
Across India, Nepal, Bangladesh and Pakistan, millions of residents have been affected and hundreds of thousands displaced, with homes and boats washed away.
In flood-prone Bangladesh, which is criss-crossed by rivers, around one-third of the country is underwater and people were being killed by lightning strikes, officials said.
In India, the death toll rose to at least 120 and entire communities were cut off by rising floodwaters, which damaged or submerged roads.
"It's been 15 days [since] this area has been flooded," a local resident in Assam, where the death toll reached 22, told AFP.
"The damage it has caused is very bad. Cattle have also been affected. Everything has been destroyed."
TRT World spoke to Rebecca Bundhun for more details.
Video footage shared on social media showed rescuers pulling a rhinoceros calf from swollen floodwaters at the state's World Heritage-listed Kaziranga National Park, which is home to two-thirds of the world's remaining one-horned rhinos.
In Bihar, which borders Nepal — and like Assam is one of the worst-affected regions in India — locals told AFP they were unable to reach food supplies.
Some 33 deaths have been reported and 2.5 million residents affected. Locals were erecting makeshift shelters on elevated land with the meagre belongings they had salvaged from the floodwaters.
In Mumbai, the number of victims from a building collapse following heavy rains rose to 13.
In the worst-affected Bangladesh district of Kurigram, deputy district administrator Hafizur Rahman told AFP a woman and four children died after their small boat sank in floodwaters.
Others were killed by landslides in Cox's Bazar district — home to nearly one million Rohingya Muslim refugees who have fled a military crackdown in Myanmar.
In Nepal, the aid agency Save the Children said severe flooding and landslides had left tens of thousands of people homeless, with many stranded outdoors or marooned.
At least 78 people have died and 16,000 families have been displaced.
"It's absolutely essential that we reach these communities to avoid this turning into a health emergency," Save the Children's Nepal country director Ned Olney said in a statement.