Floods kill more than 100 in northern India and Nepal

More than 100 people have died in floods and landslides in northern India and Nepal after days of heavy rain.

In the Indian state of Uttar Pradesh, the death toll has risen to 81. In neighbouring Nepal, 21 people died in weather-related incidents between Thursday and Sunday, according to the country's disaster management agency.

Swept downstream

Rivers rising in the Himalayas carried floodwater across the border. Bodies were recovered as far downstream as Nawalparasi district in Nepal and the Kushinagar and Maharajganj districts of Uttar Pradesh. Floods and landslides have also damaged homes, and several people remain missing.

A dangerous season

The region is still in the tail end of the monsoon, the rainy season that runs from about June to September and brings most of South Asia's annual rainfall. Monsoon rains are essential for farming and water supplies, but heavy downpours regularly cause deadly floods and landslides, especially in mountainous areas.

Nepal's steep terrain makes it particularly vulnerable to landslides, which can bury homes and cut off roads. In Uttar Pradesh, one of India's most populous states, flooding along rivers that flow down from the Himalayas affects millions of people most years.

Snow in the mountains

The same weather system brought heavy snow to Nepal's high mountains. An avalanche struck the base camp of Himlung in Manang district on Sunday, killing at least four people, with at least 14 expedition staff missing.

A changing climate

Scientists say that a warming climate is making extreme rainfall more intense, because warmer air can hold more moisture. That is increasing the risk of floods and landslides across South Asia, where hundreds of millions of people live in areas exposed to monsoon hazards.

The monsoon

The South Asian monsoon brings most of the region's rain between June and September. It is vital for farming, but heavy downpours regularly cause floods and landslides, especially in hilly and mountainous areas.