'20 million cubic litres of water was coming at 160 km per hour!'

Residential areas devastated by mud-laden floodwaters in Nepal. Photograph: Nepal's TV Today/ANI Video Grab

Shobha Warrier, September 4, 2026, Kathmandu : 'The valley is around 16 km from the Nepal border, and it took just 8-10 minutes for the ice and rocks to reach the Nepal border. You can imagine how fast it must have travelled!'

What Nepal and Tibet experienced on the 26th of August 2026 can be described as one of the worst natural disasters human beings have seen in recent times.

Though scientists and environmentalists have been warning about the consequences of global warming, the flash floods due to glacier melting is just an indicator of what the world is going to see in future.

"We feel so bad because Nepal has 0% contribution to global warming. But we the mountain people of this region are the ones who are taking the burden. We are the first ones to suffer on such a large scale due to global warming," Professor Bishal Nath Upreti, former head of the department of geology at the Institute of Science and Technology, Tribhuvan University, Nepal, and the president of Nepal Centre for Disaster Management tells Rediff's Shobha Warrier.

The melting of the glaciers and the subsequent floods that happened in Nepal and Tibet took everyone by surprise...

Yes. I would like to tell you what might have happened.

Mount Langtang Lirung is massive, standing at 7,234 metres high along the Nepal-Tibet border, and there are glaciers at very high altitude on both sides of the ridge.

What will happen when a chunk of this glacial ice with rocks suddenly falls down from more than 1 kilometre height?

It rushes down the slope to the river at very high speed and blocking the river for a few minutes.

Since we did not know what exactly happened, people assumed that there was a glacial lake burst.

In fact, a year ago, there was a glacial lake burst in Tibet, and it had destroyed a lot of infrastructure, and bridges in the same area

Immediately after the glacier melt, an earthquake of 5.2 on the Richter Scale was recorded. So, we thought it was because of the earthquake that ice fell down from the cliff and resulted in this disaster.

Later it was clarified that it was not a tectonic earthquake, but an impact earthquake caused by the fall of the glacier.

This information completely changed the scenario. Now we know that it is not the earthquake that triggered the fall of the ice, but it is the ice and rock fall that caused an earthquake of this magnitude.

The valley is around 16 km from the Nepal border, and it took just 8-10 minutes for the ice and rocks to reach the Nepal border. You can imagine how fast it must have travelled!

It was 8.37 in the morning.

It means there is no possibility of an early warning as nobody was aware of what was happening.

It was not just water that came down but mud, rocks, glacial ice, and everything it caught on its way. When it reached the bridge, it was almost 100-200 metres high.

A home damaged and surrounded by thick mud and debris following the flash floods in Nuwakot. Photograph: ANI Video Grab

Like a tsunami?

See, tsunami has only water. Here, there was more; big boulders of rocks, ice, sand, and trees.

And around 20 million cubic litres of water was coming at an average speed of 160 km per hour!

This is what we know right now. It needs a lot more time for people to go to the field and conduct research.

Many experts say that it is very difficult to predict glaciers melting. Why is it so?

In this case, it was not just the melting of a chunk of ice.

There are many other issues behind this phenomenon.

Because of warming, the average temperature in this area has gone up. Because of the heat, glaciers have started melting which results in them falling down. This is one possibility.

Global warming is definitely one of the key reasons behind a disaster like this.

Due to global warming, glacial melting happens and it results in what we call glacial lakes.

The number of glacial lakes is increasing day by day in this region because of the rise in temperature.

These glacier lakes are becoming larger and larger in size too.

Out of a regional total of 46 high-risk glacial lakes across the Koshi, Gandaki, and Karnali river basins, 21 are located inside Nepal, while 25 sit just across the border in Tibet. It means we have around 46 glaciers right over our head, and they can breach anytime.

And when one of these breaches, it will greatly affect our part of the country.

That is why we need the cooperation, collaboration and joint research of our neighbouring countries so that we have early warnings of any disaster.

Early warning is the only way to save lives and property on the downstream.

A recent study by IIT Kharagpur said that the Himalayan mountain areas as warming faster the plains.

Absolutely correct. Compared to the plains, the higher mountain areas are warming faster.

Because of the warming, the glaciers are melting very fast in the Himalayas.

When glaciers melt, it creates big glacial lakes.

Since global warming is a reality, how much are people living in the valleys, and the coastal areas in danger?

A lot of studies have shown that the sea is rising due to global warming.

Unlike the sea rising which is a slow process, glacier melting results in a dangerous situation where millions of cubic litres of water rush through a very narrow valley.

The water level can be 5 to 10 times higher than the level a normal flood.

This is the real challenge as people living in most of our villages, whether it is in India or Nepal, are at the river level.

Are we going to see more and more natural disasters like this? Is disaster management the only solution?

There are two things. The glacial lakes in the high mountains will not get dry as ice is going to melt.

You cannot drain those waters also, like they tried to reduce the water level in South America. In fact, it collapsed during the construction itself.

So, lowering the level of water in the glacial lakes is a dangerous thing to do.

What we can do is, give early warning to save lives. This is the only way.

We have the technology now. We have the satellites. We have the seismometers.

For example, like it happened this time when the glacier falls, it creates an earthquake and vibrates the ground. This can be picked up by the seismometers. Remember the magnitude was 5.2 on the Richter Scale which is a big earthquake.

If seismometers are placed near the glacial lakes, when the lake gets breached, it will create an initial earthquake which can be picked up by the seismometers.

Similarly, we can use satellites to monitor glacial lakes.

Remember the Chamoli flash floods of 2021. It was similar to what happened in Nepal now. 200 people died then but here, the death toll has already crossed 5,000.

Because of global warming, the number of such disasters could increase in future.

In the Himalayan region in India also, you have hundreds of large glaciers. In Bhutan and in Sikkim also. In Nepal, we have more than 3000 glaciers.

The International Centre for Integrated Mountain Development -- ICIMOD -- has already done extensive studies all over the Himalayas, Karakoram and Tibet areas to locate glaciers, and glacial lakes, and to find out how dangerous they are.

What we need urgently is early warning.

For that, we need more research, more collaboration between India, Nepal and China. Only if we have cooperation, collaboration, and joint early warning system, we can save lives.

What happened now has to be an eye-opener.

We know now that this is equivalent to the 2015 Nepal earthquake in terms of loss. The human loss then was more than 9,000.

The preliminary estimate by the Nepal government says, the loss this time is around $5 billion.

The loss is huge in terms of property, and hydro power stations.

This is one of the biggest disasters Nepal has seen in the recent years, after the 2015 earthquake.

A Nepalese helicopter conducts rescue operations in the flash-flood-ravaged areas in Rasuwa. Photograph: ANI Video Grab

Many scientists say, around 15 million people worldwide are living in danger zones, especially in the Himalayan, Hindu Kush, Karakoram mountain ranges in Asia...

It is true.

Even in our limited area, we are talking about 1.6 million people getting affected by this one disaster. Over 5,000 people are missing or dead. So, you can imagine the kind of challenging times ahead.

We feel so bad because Nepal has 0% contribution to global warming. But we the mountain people of this region are the ones who are taking the burden. We are the first ones to suffer on such a large scale due to global warming.

We are the fourth country in the world that is the most affected by global warming now.

As a Nepali, one feels very sorry that we are in such a dire situation because of climate change.

Should the world be once again looking at development without disturbing nature's balance?

Obviously. But who will bell the cat?

Big countries contribute so much to polluting the world.

India is going towards green energy.

China is also going towards green energy.

US is also going but not as much as the other countries.

It is the Europeans who have done tremendous work in the field of green energy. They are very concerned.

By the end of the century, we will see an exploding scenario.

At least if you stop or reduce emissions now, at least, it will be less disastrous in future.

A combination of satellite images shows the valleys near the Nepal-China border on August 25, 2026, before the devastating floods and on August 26, 2026, after the disaster. Photograph: Planet Labs PBC/Reuters

There was a controversy regarding the IPCC 2007 report in which it was mentioned that the Himalayan glaciers would melt away by 2035. In the 2010 report, they said it was a mistake. But the way things are going, are we not moving towards such a scenario?

It may not be the entire glacier, but we are seeing a glimpse of what the IPCC had written at that time.

The rise in global temperature is more than what was expected earlier. For example, in the early days, nobody thought of what you call the thawing of permafrost.

Permafrost is frozen rock, ice and soil which you see at high altitude, and it stays on ground at or below 0 Degree Celsius for many years.

When permafrost thaws, it releases massive amounts of carbon dioxide and methane as the frozen organic matter decomposes, creating a dangerous situation that accelerates global warming.

Today, there are millions of square kilometres of permafrost that release carbon dioxide because of global warming.

This will have a cascading effect.

So, may not be in 2035 but by 2050 or 2070, the Himalayas may not be the same. Maybe by the end of century, we may not even have any glaciers in this area. We are heading towards that direction as our glaciers are receding so fast all over the Himalayas and in Tibet.

If it happens, we in South Asia should be more concerned as there will be no water in our rivers like the Ganges, the Sutlej and the Brahmaputra.

It will be a matter of concern for the two billion plus people in the South Asian region.

As a scientist, what will you tell the world?

Global warming is a reality. You can't just close your eyes and say, there is no climate change.

The train has already started moving, and it is gaining speed.

There is no other option but stop it but you can't stop it in seconds.

The time has come for the world to apply the brakes now itself as it takes some time before it stops. Only after it stops can we recover for the future.

Professor Bishal Nath Upreti.