At least 65 people have died in a series of flooding and landslide events in Nepal and India since Friday 3 October 2025. The majority of the deaths have occurred in the Ilam District of Nepal, where 37 people have died in a series of landslide events, with many more still missing. At least eight more people have been killed in floods, landslides, and lightning strikes elsewhere in Nepal. In India, at least 20 people have died in flash floods and landslips in the Darjeeling District of West Bengal, which borders onto Ilam District in Nepal.
The events are associated with heavy rains caused by an ongoing Monsoon Season in Nepal, which typically begins in June and ends around the middle of September. The annual monsoon in Nepal claims a large number of lives each year, and late rains such as these bring with them additional problems, as by September the ground in low lying areas of Nepal is often waterlogged, and the waters rivers and lakes high, if not actually overflowing. This means that even if the rains stop soon, their effects are likely to be felt for some time yet. Sadly, while late rains were once a rare event, they are becoming more common as a result of global warming, which is resulting in a hotter, wetter climate in the region.
Monsoons are tropical sea breezes triggered by heating of the land during the warmer part of the year (summer). Both the land and sea are warmed by the Sun, but the land has a lower ability to absorb heat, radiating it back so that the air above landmasses becomes significantly warmer than that over the sea, causing the air above the land to rise and drawing in water from over the sea; since this has also been warmed it carries a high evaporated water content, and brings with it heavy rainfall. In the tropical dry season, the situation is reversed, as the air over the land cools more rapidly with the seasons, leading to warmer air over the sea, and thus breezes moving from the shore to the sea (where air is rising more rapidly) and a drying of the climate. This situation is particularly intense in South Asia, due to the presence of the Himalayas. High mountain ranges tend to force winds hitting them upwards, which amplifies the South Asian Summer Monsoon, with higher winds leading to more upward air movement, thus drawing in further air from the sea.
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