Six people have been killed in floods precipitated by torrential rains across northeast India and neighbouring Bangladesh that inundated the homes of more than a million others, officials said on Wednesday.

Monsoon rains cause widespread destruction every year, but experts say climate change is shifting weather patterns and increasing the number of extreme weather events.

Disaster authorities in India’s northeastern state of Assam said four people had died over the past day, bringing the number of people killed there over successive downpours since mid-May to 38.

In Bangladesh, landslides triggered by heavy monsoon rains killed two people including a Rohingya refugee early on Wednesday, police commander Jahirul Hoque Bhuiyan told AFP.

Bhuiyan said authorities in Bangladesh’s vast relief camps — home to around a million Rohingya refugees from neighbouring Myanmar — had relocated some inhabitants to safety.

The worst flooding took place in the northeastern Sylhet division, where top government bureaucrat Abu Ahmed Siddique said more than 1.3 million people had been affected.

“Their villages and roads and most of their homes have been inundated by flood water,” Abu Ahmed Siddique, the government administrator of Sylhet region, told AFP.

Kamrul Hasan, the secretary of Bangladesh’s disaster management ministry, said that rivers had swelled after rain upstream in India.

Much of low-lying Bangladesh is made up of deltas as the Himalayan rivers of the Ganges and Brahmaputra slowly wind towards the sea after coursing through India.

Hasan told AFP that hundreds of relief shelters had been opened around Sylhet for those forced out of their homes by flood waters.

‘Higher ground’

India’s weather department has issued alerts for Assam and neighbouring states warning of the risk of more flash floods.

Flood waters have damaged roads in the state, and the air force rescued 13 fishermen stranded on an island.

A major portion of the Kaziranga National Park, a UNESCO World Heritage site and home to the highest number of one-horned rhinos in the world, has also been flooded.

“Forest guards have been put on alert,” park official Arun Vignesh told AFP. “Hundreds of animals have started crossing the highway in search of higher ground”.

The summer monsoon brings South Asia 70-80 per cent of its annual rainfall, as well as death and destruction due to flooding and landslides.

The rainfall is hard to forecast and varies considerably, but scientists say climate change is making the monsoon stronger and more erratic.

Last week, at least 14 people were killed after rains triggered landslides, lightning, and flooding in Nepal.

In Bangladesh, at least nine people died in a landslide in June.

The same month, six people were killed in flash floods and landslides in Sikkim, an Indian state in the Himalayan foothills bordering China.