Relentless monsoon rainfall produces deadly flooding in Bhutan, forces dramatic rescues in Nepal

Heavy rainfall triggered severe flash flooding in the south Asian nations of Bhutan and Nepal this week, killing 11 and leaving an additional 25 missing.

Heavy monsoon rainfall that arrived over parts of northeastern India, Bangladesh, Nepal and Bhutan late last week persisted throughout the weekend and much of this week. Residents in the Himalayan region of Nepal and Bhutan were caught off guard Wednesday after rivers and streams rushed out of their banks.

At least 11 people were killed at a development site near the town of Melamchi, Nepal after floodwaters swept through the area early in the morning, according to Reuters. Melamchi is located to the northeast of Kathmandu, the capitol of Nepal.

Partially submerged houses are seen as floodwater from the swollen Melamchi River enters the village in Sindhupalchok, Nepal, June 16, 2021. (REUTERS/Navesh Chitrakar)

The development site was reported to be building a drinking water project, officials said.

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According to Reuters, two helicopters were sent to the camp to rescue injured villagers while members of the country's military walked 11 hours from the nearest road to assist with evacuations.

In Nepal, heavy rains Tuesday night caused the Melamchi River to burst its banks in the Sindhupalchowk district.

Since Tuesday, heavy rain and flooding has damaged roads, bridges, homes and washed away farmland and livestock across the region.

People gather on higher ground as flood water from the swollen Melamchi River enters the village in Sindhupalchok, Nepal, June 16, 2021. (REUTERS/Navesh Chitrakar)

Some witnesses reported that some residents were able to grab belongings and move to higher ground, while army helicopters rescued residents from rooftops after becoming trapped by floodwaters.

The heavy rainfall in Nepal and Bhutan was fueled by a monsoon low that formed in the northern Bay of Bengal late last week. This low helped speed up the arrival of the southwest monsoon over northeastern India and has enhanced rainfall across the area and into Bangladesh and Myanmar.

According to AccuWeather Lead International Meteorologist Jason Nicholls, the low moved over India's northeast coast last weekend then over Jharkhand and eastern Uttar Pradesh in northern India through the beginning of the week.

Partially submerged houses are seen as flood water from the swollen Melamchi River enters the village in Sindhupalchok, Nepal, June 16, 2021. (REUTERS/Navesh Chitrakar)

"[This monsoon low] produced heavy rainfall over central and eastern Nepal and into Bangladesh," Nicholls added. "The moist air from this low being pushed up the foothills of the Himalayas also helped enhance rainfall in the areas hardest hit."

Since June 1, parts of Nepal and Bhutan have already reported over 14 inches (356 mm) of rainfall.

While this monsoon low gradually dissipated over north-central India late this week, another monsoon low is forecast to follow in the first low's footsteps.

This next monsoon low will keep enhanced rainfall over southern Myanmar, southern Bangladesh, northeast India, Nepal and Bhutan through the weekend.

Areas of heavy rainfall can aggravate existing flooding and create new areas of flooding.

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