Sky rivers: The invisible floods haunting South Asia
For decades, scientists have whispered about sky rivers – vast, invisible torrents of water vapour snaking through the atmosphere, unseen but immensely powerful.
Today, that quiet scientific curiosity has turned into a roaring alarm. What once sounded like science fiction is now a terrifying reality: Sky rivers are here, and they are reshaping the climate, lives, and landscapes of South Asia.
Unlike land rivers, which can be dammed, diverted, or monitored, atmospheric rivers, as they are scientifically known, cannot be controlled. They move with the wind, dictated by the whims of a warming planet. And when they burst, they don’t just flood villages – they flood nations.
What is an atmospheric river?
An atmospheric river is a narrow corridor of concentrated moisture in the sky, stretching thousands of kilometres across the atmosphere. Think of it as a flying river, invisible to the naked eye, carrying more water than the Amazon.
These rivers form over warm tropical oceans, where rising temperatures evaporate vast amounts of water. The moist air is then carried by wind currents toward cooler regions, where it condenses into clouds and unleashes torrential rainfall in a short span.
On average, an atmospheric river spans: 2,000 km long, 500 km wide, 3 km deep, and even can extend up to 5,000 km in extreme cases.
And when it rains? 200 to 500 millimetres in just 24 to 72 hours – enough to drown cities.
In 2023, a single atmospheric river dumped 250 mm of rain in one day on California.
In June this year, Cherrapunji, India, already famed for its rains, received 164 mm in 24 hours, triggering flash floods that swept into Chittagong, Noakhali, and Feni in Bangladesh.
The rain may not have fallen directly on Bangladesh – but its impact did.
At Amalshid, the water level of the Kushiyara River surged by 191 cm in just 24 hours. Experts say 300 mm of rain can trigger a 10-day flood. We are now living in that era.
Why are sky rivers becoming more frequent?
The answer is simple: global warming.
As ocean and air temperatures rise, more water evaporates, feeding these atmospheric rivers with unprecedented intensity. Climate change is not just increasing their frequency – it’s changing their path.
Jet streams, the high-altitude winds that steer these rivers, are shifting due to polar warming. As a result, sky rivers are now reaching places they’ve never hit before: Arid deserts of Afghanistan, drought-stricken regions of Pakistan, and even parts of the Middle East.
Meteorologists warn: what was once a rare phenomenon is becoming routine. And South Asia, already one of the most flood-prone regions on Earth, is on the front lines.
Last month, nine Indian Army personnel went missing in a flash flood in Harsil, Uttarakhand, triggered by an atmospheric river. Experts say such events will only grow more common. Till Saturday, 300 people of a single village in northern Pakistan die from flash flood caused by cloudburst.
Bangladesh in the crosshairs
Recent satellite data and climate models show a sharp rise in flood intensity across Bangladesh due to atmospheric rivers. And August 2025 could be just the beginning.
Meteorologist Mustafa Kamal Palash warned on social media that 5 to 10 districts face flood risk within 24 hours, and 10 to 15 districts in the next 72 hours.
By August 17, 15 to 20 districts across Rangpur, Rajshahi, Khulna, Dhaka, and Mymensingh divisions could be under water.
Rivers like the Teesta and Dudhkumar in Rangpur are already flowing above danger levels. With no dams to stop the sky, and no warning systems tuned to these invisible floods, millions are vulnerable.
A regional nightmare
Atmospheric rivers are no longer just a meteorological term – they are a regional emergency. From the Himalayan foothills to the Bay of Bengal delta, millions now live under the shadow of a river they cannot see.
And unlike traditional floods, which follow predictable seasonal patterns, sky rivers strike fast and without warning. They don’t care about borders, politics, or preparedness. They come, they flood, they vanish—leaving behind ruined homes, broken lives, and lost futures.
What can be done?
Early Warning Systems: Bangladesh and its neighbours need satellite-based monitoring and real-time forecasting tailored to atmospheric rivers.
Regional Cooperation: These rivers don’t stop at borders. India, Bangladesh, Nepal, and Bhutan must share data and coordinate disaster response.
Climate Action: Reducing emissions is no longer a distant goal—it’s a survival strategy.
The sky is no longer safe
We once looked up to the sky for calm, for beauty, for hope. Now, we look up with fear.
The rivers above us are rising. And unless we act fast they will drown us all.