What Nepal’s flash flood and landslide can teach Bangladesh

It was half past eight on a Wednesday morning. The quiet hill settlements of Rasuwa district, on the Nepal-Tibet border, had barely stirred awake. At that moment, a modest 4.4-magnitude earthquake in the Tibetan region sent tremors into an already unstable Himalayan glacier.

Within moments, a mass of ice and rock collapsed, blocking a river's course and forming a makeshift lake — which then burst, unleashing a devastating flash flood.

Village after village was swept away in an instant. As this piece is being written, the death toll has crossed 900, with roughly 4,200 people missing.

Experts are calling it Nepal's worst natural disaster since the catastrophic 2015 earthquake. Homes, roads, hydropower stations, bridges — the scale of destruction is still being assessed, but there is no doubt it is immense.

This kind of disaster is nothing new for Nepal. Nestled in the lap of the Himalayas, the country has long been recognised as a high-risk zone for earthquakes, landslides, and Glacial Lake Outburst Floods (GLOFs). The 7.8-magnitude earthquake of 25 April 2015 killed nearly 9,000 people and injured about 22,000. 

Before that, in 2014, a devastating landslide in Jure village of Sindhupalchok district claimed over a hundred lives. Towering mountains, steep slopes, unstable glaciers, and dense settlements below them — this combination has made Nepal one of the most disaster-prone regions on earth.

Sudden water disasters, however, are not exclusive to the Himalayas — they are a recurring terror throughout human history. The 1975 collapse of the Banqiao Dam in China's Henan province is estimated, by various accounts, to have caused close to 200,000 deaths, direct and indirect, making it one of history's worst dam disasters.

Then there is the tsunami that struck Pangandaran beach on Java's coast on 17 July 2006, triggered by a 7.7-magnitude undersea earthquake. Arriving without warning, the waves killed at least 668 people, injured roughly 9,300, damaged thousands of homes, and caused an estimated $45 million in economic losses. 

Both events are reminders of how catastrophic nature's unpredictability can become when paired with weak early-warning systems.

Bangladesh, too, is no stranger to this list. The cyclone and storm surge that struck the southeastern coast on 29 April 1991 killed nearly 139,000 people and left about 10 million homeless. A storm surge nearly six metres high devastated the Chattogram-Cox's Bazar coastline.

Cyclone Sidr in 2007 and Aila in 2009 remain fresh in memory. Sidr killed several thousand people and destroyed hundreds of thousands of homes. Aila, though comparatively less deadly, breached coastal embankments and left behind long-term waterlogging and salinity damage that has still not fully healed.

The history of landslides is no less tragic. On 13 June 2017, three consecutive days of heavy rain triggered landslides in Rangamati that killed 120 people, including army personnel — 25 of them in the Shimultali area alone. Eleven more died in Naniarchar in 2018, and several others in Kaptai in 2019.

Every monsoon, thousands of people in the Chattogram Hill Tracts still live at the foot of hills at their own risk. This July, hill floods and landslides across five districts of Chattogram division killed around 55 people and affected nearly 900,000 — proof that this risk has not diminished, but grown.

The question of how much climate change is driving these disasters is now unavoidable. Scientists remain cautious about attributing any single event directly to climate change, but the trend is unmistakable. Rising global temperatures are melting Himalayan glaciers faster, creating new, unstable glacial lakes that could burst at any moment.

At the same time, monsoon behaviour is shifting — short bursts of extreme rainfall are becoming more frequent, raising the risk of flash floods and landslides in both Bangladesh and Nepal. Compounding this is unplanned development: hill-cutting, deforestation, and construction along natural river channels. It is this interaction between nature's fury and human error that is making disasters increasingly lethal.

So, can such disasters be prevented at all? Events like earthquakes or glacial lake outbursts cannot be stopped entirely. But the human and economic toll they exact can be significantly reduced — if preparedness and early-warning systems are given the priority they deserve.

Disaster-prone countries such as Japan, Chile, and the Philippines have shown that early-warning systems combined with an aware population can save thousands of lives — just as the absence of such systems cost so many lives in Indonesia in 2006.

Satellite monitoring could be the most effective tool here. Regularly tracking unstable Himalayan glacial lakes through satellite imagery to identify dangerous lakes and issue timely warnings is now entirely feasible, technologically.

Since Nepal, China, India, and Bangladesh share interconnected river basins, building a joint regional risk-mitigation framework is essential. Organisations like International Centre for Integrated Mountain Development (ICIMOD) have taken initiatives toward such coordination, but political constraints often obstruct data sharing.

Yet a timely warning issued upstream can save countless lives downstream — as seen after this disaster, when warnings issued in India's Bihar and the Gandak river basin allowed at least some preparation. Alongside this, community-based preparedness is essential: evacuation drills for people in high-risk areas, rapid rescue systems, and discouraging settlement in dangerous zones while creating alternative resettlement opportunities.

Bangladesh has much to learn from this disaster. Our geography places us at risk both as a river-fed plain and as a hilly region. When a glacial lake bursts or extreme rainfall occurs upstream, its effects flow directly into the Brahmaputra, Teesta, or Meghna basins. At the same time, we face landslides in the Chattogram Hill Tracts, cyclones and storm surges on the coast, and riverbank erosion and flooding in the lowlands — few countries in the world face this triple threat simultaneously.

Rising sea levels, intensifying cyclones, and erratic upstream rainfall — these three trends will only pose harder challenges for Bangladesh in the years ahead. A mere one-metre rise in sea level is estimated to submerge nearly 17% of Bangladesh's land.

As we plan for the future, a few priorities demand our immediate attention:

Firstly, strict enforcement of laws against hill-cutting in hilly regions, paired with guaranteed alternative resettlement. Reckless stone extraction that destroys the environment must also be halted through firm legal action.

Secondly, regional river-data sharing must rise above political constraints to build an effective South Asian early-warning network.

Thirdly, both coastal embankments and hill slopes need infrastructure built on climate-resilient engineering principles.

Fourthly, local disaster management committees must be made genuinely capable through real training and resources — not left as names on paper.

Nepal's disaster is a fresh reminder of how helpless humanity can be before the forces of nature — but also that with preparedness and foresight, much of that helplessness can be brought under control.

At this painful moment for our neighbour, our sympathy is essential — but so is honest self-reflection about our own vulnerabilities. Disaster will come again. The question is: How prepared will we be?

Sketch: TBS

M M Mahbub Hasan is a banker, development researcher and author.