NEW DELHI (AFP, REUTERS) - The death toll from days of flooding and landslides in India and Nepal crossed more than 100 on Wednesday (Oct 20), including several families swept away or crushed in their homes by avalanches of mud and rocks.

Experts say that they were victims of ever-more unpredictable and extreme weather across South Asia in recent years caused by climate change and exacerbated by deforestation, damming and excessive development.

In Uttarakhand in northern India, officials said that 46 people had died in recent days with 11 missing.

At least 30 of those were killed in seven separate incidents in the Nainital region early on Tuesday, after cloudbursts - an ultra-intense deluge of rain - triggered a series of landslides and destroyed several structures.

Television footage and social media videos showed residents wading through knee-deep water near Nainital lake, a tourist hotspot, and the Ganges bursting its banks in Rishikesh.

The floods almost swept away an elephant near the Corbett Tiger Reserve - home to 164 of the big cats and 600 elephants - but in a video that went viral, the animal managed to battle the strong currents and swim to safety.

Uttarakhand reported 178.4mm of rain in the first 18 days of October - almost 500 per cent more than the average, the Hindustan Times reported, citing Indian Meteorological Department data.

And the state's Mukteshwar area reported 340.8mm rainfall in the 24 hours until Tuesday morning, the most since the weather station was set up there in 1897, the newspaper said.

The Indian Meteorological Department forecast a "significant reduction" in rainfall in the state from Wednesday.

Five of the dead were from a single family whose house was buried by a massive landslide, local official Pradeep Jain said.

Aerial footage of the affected areas showed engorged rivers and villages partially submerged by floodwaters.

"There is huge loss due to the floods… the crops have been destroyed," Uttarakhand Chief Minister Pushkar Singh Dhami told ANI after surveying the damage late on Tuesday.

"The locals are facing a lot of problems, the roads are waterlogged, bridges have been washed away."

In Kerala in the south, Chief Minister Pinarayi Vijayan said that the death toll had hit 39 there.

The coastal state has been battered by heavy rain since last Friday and thousands have been moved to safer locations. More than 200 homes were destroyed and almost 1,400 damaged.

Kerala has also seen an increase in natural disasters, including in 2018 when nearly 500 people perished in the worst flooding in a century.

Environmentalists blame an increase in extreme weather in the warming Arabian Sea as well as excessive development in the Western Ghats mountain range.

After a brief respite, forecasters are warning of more heavy rain in the coming days with alerts issued in several places in Kerala.

Shutters on at least three dams across the state were opened Tuesday including Idukki, one of Asia's biggest, though State Electricity Board chairman B. Ashok said "there was no need to panic".

Indian Prime Minister Narendra Modi said in a tweet he was "anguished" by the loss of life.

The Himalayan state of Uttarakhand is especially prone to flooding, but experts say they are becoming more common as rains become increasingly erratic and glaciers melt.

Experts also blame deforestation and the construction of hydroelectric dams.

In February, a ferocious flash flood hurtled down a remote valley in Uttarakhand, killing around 200 people. The state has reported over 7,750 extreme rainfall events and cloudbursts since 2015 - a majority of them in the last three years.

Unseasonally heavy rains across India have led to deadly floods in several areas of the country in recent days.

In Nepal, disasters management division official Humkala Pandey said: "In the last three days, there have been 31 deaths from floods and landslides triggered by heavy post-monsoon rainfalls across the country. Forty-three people are missing."

He added: "It's still raining in many places. We are still compiling data from the field. The death toll could go up further."

In the eastern district of Dhankuta, a landslide buried a house overnight, killing six people including three children.

Swelling rivers flooded homes in several districts, damaging roads and bridges and reportedly destroying crops.