Chencho Dema

Extreme weather is no longer a distant global headline—it’s hitting home in the fragile Himalayas. Bhutan has experienced an unprecedented surge in extreme weather events, with a record 10 incidents in just the last three years.

The National Centre for Hydrology and Meteorology (NCHM) attributes this alarming spike to climate change, noting that erratic precipitation patterns and unpredictable low-pressure systems have made flash floods increasingly common.

The country’s vulnerability to the whims of nature has become more apparent than ever, underscoring the urgent need for climate resilience in the region.

In the span of six years from 2019 to 2024, Bhutan has been battered by 52 extreme weather events, ranging from flash floods and heavy snowfall to erratic pre- and post-monsoon disturbances. These events have claimed lives, destroyed crops, and ravaged properties, leaving communities and ecosystems vulnerable. Extreme weather events, such as these, are characterised by unusually severe conditions, often short-lived but devastating in impact.

The numbers tell a worrying story: six events in 2019, rising to 10 in 2020, peaking at 12 in 2021, and continuing with seven each in 2022 and 2023. As of August 31, 2024, the country has already faced 10 extreme weather incidents, signaling a troubling trend linked to climate change.

This year, Bhutan has witnessed a series of destructive extreme weather events, most notably the flash floods in Bumthang on August 5, Dechencholing in Thimphu on August 10—where a 56-year-old man tragically lost his life—and Gangtey in Phobjikha on August 18. Several landslides and road blockages further compounded the damage. Additionally, a rare glacier lake outburst floods (GOLF) event struck on October 30 last year.

In 2023, heavy rainfall triggered numerous flash floods, but the most devastating was the Ongar flash flood in Lhuntse on July 20, which claimed 24 lives.

A decadal analysis shows a marked increase in extreme weather events in Bhutan, rising from just two in 1968 to 46 between 2010 and August 2021. While the NCHM reports that Bhutan typically sees three to four flash floods annually, determining a clear link between the rise in frequency or intensity of such events and recent years remains complex. Flash floods, historically driven by rainfall and glacier melt, have always been a persistent threat, though their impacts continue to grow in severity.

Geographically, Bhutan’s southern belt—including areas like Gelephu, Phuentsholing, and Samtse—bears the brunt of heavy rainfall and, consequently, experiences more frequent flash floods. Around 70 percent of the country’s total rainfall is concentrated in the monsoon months from June to September, making this period the peak season for flash floods.

Despite the rise in extreme weather events globally, Bhutan’s total rainfall for this year remains within the normal range. However, officials from the NCHM caution that the country can expect an increase in weather disturbances, particularly more frequent convective thunderstorms, as a result of climate change.

  Rising global temperatures have altered precipitation patterns and accelerated glacier melt. The Indian Monsoon, which is crucial for Bhutan’s weather and a primary source of water, has become increasingly unpredictable due to climate change. Variations in atmospheric circulation, driven by global warming, have affected the timing, duration, and intensity of monsoon rains, according to an official.

Currently, NCHM operates three Flood/GLOF Early Warning Systems EWS in major river basins where potentially dangerous glacial lakes  are located. These systems are installed in the Punatshangchhu basin (Phochhu and Mochhu), the Mangdechhu river basin, and the Chamkharchhu basin.

Designed to monitor and issue alerts for GLOFs downstream, these systems face significant challenges. While effective for flood monitoring and warning, their maintenance and operation are hindered by remoteness, technological changes affecting spare parts, and difficulties in accessing reliable communications.

Flash floods, which are common in mountain regions and often triggered by rainfall, are difficult to predict. Monitoring and installing EWS along small streams is challenging due to the extensive network of streams and the substantial investment required.