Glacial Floods, Climate Change, and What the U.S. Can Learn from the Himalayas Disaster

Field evidence of sediment aggradation.
Field evidence of sediment aggradation. (A to F) Photographs taken along the Teesta River show the aggradation of the sediments transported by the flood cascade and its impact. Latitude, longitude, and elevation (in m a.s.l) are at top right; locality name and distance from SLL are at bottom right. Photo credits: Praful Rao (study co-author).

A Disaster Unfolds

Imagine waking up in the middle of the night to a roaring wall of water crashing through your town. That’s what happened in Sikkim, India, on October 3, 2023. A glacial lake high in the Himalayas burst suddenly, sending a flood of 50 million cubic meters of water rushing downstream. Villages were washed away, bridges collapsed, and a massive hydropower dam was completely destroyed.

The flood traveled 385 kilometers, even reaching parts of Bangladesh. This was no ordinary flood—it was a Glacial Lake Outburst Flood (GLOF), a type of disaster that’s becoming more frequent as the planet warms.

What Caused the Flood?

At the heart of this disaster was South Lhonak Lake, one of the fastest-growing glacial lakes in the Himalayas. Scientists have been watching it for years, warning that its natural dam—made of ice and rock—was getting weaker.

Then, the worst happened:

  • A 14.7-million cubic meter chunk of frozen land collapsed into the lake.
  • This triggered a 20-meter-high wave—as tall as a six-story building.
  • The wave smashed through the natural dam, sending a torrent of water and debris barreling down the valley.

Think of it like a bathtub overflowing, except instead of a few gallons of water, it was millions of tons rushing out all at once.

The Impact: Lives, Land, and Infrastructure Lost

The destruction was swift and brutal:

  • 55 people lost their lives, and 74 are still missing.
  • More than 7,000 people were displaced, their homes and villages washed away.
  • 31 bridges, 25,900 buildings, and 276 square kilometers of farmland were destroyed.
  • The flood carried away 270 million cubic meters of sediment—enough to fill 100,000 Olympic-sized swimming pools.

Entire communities were left without power, food, or clean water, and the road to recovery is long.

The Role of Climate Change

So, why did this happen? The simple answer: climate change.

  • The South Lhonak Glacier has been melting faster than ever, losing 0.58 meters of ice every year.
  • The lake it feeds has grown dramatically in the past few decades.
  • Warming permafrost (frozen soil) is making mountain slopes unstable, increasing the risk of landslides and dam failures.

This isn’t just a Sikkim problem—glaciers around the world are melting at record speeds, putting millions of people at risk.

Could This Happen Again?

Unfortunately, yes. Scientists warn that South Lhonak Lake is still unstable.

  • The natural dam is eroding, making another flood likely.
  • Riverbanks weakened by the last flood could collapse, leading to more destruction.
  • Extreme rainfall—which is increasing due to climate change—could trigger another disaster.

And it’s not just Sikkim—other glacier-fed lakes in the Himalayas, the Andes, and even North America are showing similar warning signs.

Why This Matters

If you think this is just a distant problem, think again. The same climate forces that caused the Sikkim flood are also affecting other mountainous regions worldwide.

Melting Glaciers Are a Global Issue

Glaciers are retreating in Alaska, the Rocky Mountains, and the Pacific Northwest. As ice melts at a faster rate, more glacial lakes are forming, increasing the chances of floods like the one in Sikkim. If we don’t prepare, communities in mountainous regions of the U.S. could face similar disasters.

U.S. Disasters Are Increasing

The 2022 Yellowstone flood destroyed roads, bridges, and homes, forcing many residents to evacuate. In California, record-breaking storms and floods are becoming more frequent, causing billions in damage. Extreme weather events—whether floods, hurricanes, or wildfires—are getting stronger, deadlier, and harder to predict.

Our Infrastructure Is at Risk

Just like the Teesta-III dam in Sikkim collapsed, many worldwide dams, roads, and power plants are vulnerable to extreme weather. Many of these structures were built decades ago and weren’t designed to handle the kinds of disasters we’re seeing today.

We Can Learn

By taking action now, the U.S. can prevent similar disasters:

  • Invest in early warning systems—monitor unstable lakes and glaciers.
  • Upgrade infrastructure—build flood-resistant bridges and roads.
  • Plan for extreme weather—ensure communities are prepared for disasters.

Preventing Another Tragedy

While we can’t stop glaciers from melting overnight, we can take steps to reduce the damage.

Early Warning Systems (EWS)

Science and technology give us powerful tools to predict disasters before they happen. Governments and scientists must monitor unstable lakes and glaciers using satellites, sensors, and AI-driven models. These systems can detect early signs of danger, giving communities valuable time to evacuate before disaster strikes. Investing in real-time alerts and community education could save thousands of lives.

Building Stronger Infrastructure

We need to rethink how we design bridges, roads, and power plants. Structures built decades ago were not designed to handle the kinds of extreme weather we’re facing today. Engineers and policymakers must ensure that new infrastructure is flood-resistant and that existing structures are reinforced to withstand future disasters. This kind of investment is expensive, but the cost of doing nothing is far greater.

Preparing for Disasters

Education and preparation can mean the difference between life and death. Governments and communities must train people on emergency evacuation plans and improve international cooperation to respond to climate disasters. Since floods and other extreme weather events are increasing, being prepared is no longer optional—it’s essential.

Addressing Climate Change at Its Root

At the core of these disasters is a warming planet. To slow down glacial melting, we need to cut greenhouse gas emissions. Governments, businesses, and individuals can all play a role by switching to clean energy sources, reducing waste, and advocating for policies that combat climate change. These actions will protect glaciers, and help stabilize global weather patterns.

A Wake-Up Call

The Sikkim flood wasn’t just a freak event—it was a preview of what’s to come if we don’t act now. The good news? We still have time to prepare. By investing in early warning systems, better infrastructure, and climate solutions, we can reduce the risk of future disasters—both in the Himalayas and here at home.


Source: Sattar, A., Cook, K. L., Rai, S. K., Berthier, E., Allen, S., Rinzin, S., Van Wyk de Vries, M., Haeberli, W., Kushwaha, P., Shugar, D. H., Emmer, A., Haritashya, U. K., Frey, H., Rao, P., Gurudin, K. S. K., Rai, P., Rajak, R., Hossain, F., Huggel, C., … Younis Bhat, S. (2025). The Sikkim flood of October 2023: Drivers, causes, and impacts of a multihazard cascade. Science.

Navigating the Storm: How Climate Change Influences Mortgage Defaults in Florida

Flooding caused by Hurricane Florence. Public domain image by the National Guard of the United States.
Flooding caused by Hurricane Florence. Public domain image by the National Guard of the United States.

In an era where climate change is increasingly influencing financial stability, a new study sheds light on how extreme weather events like heavy rains and tropical cyclones affect mortgage defaults and prepayments. This topic, first brought into focus by Mark Carney, former Governor of the Bank of England, has been a growing concern among financial regulators worldwide.

Weather Extremes and Mortgage Risks

The study, conducted in Florida, involved analyzing a massive dataset of 69,046 loans, amounting to over 3.7 million loan-month observations. Florida, known for its vulnerability to hurricanes and floods, serves as an ideal case for this study. The researchers used an innovative Cox proportional hazard model, incorporating spatiotemporal characteristics and weather variables, to examine the influence of weather extremes on mortgage risks.

Key Findings

  • Impact of Tropical Cyclones: The study reveals a significant, non-linear relationship between the intensity of tropical cyclones and mortgage defaults. The risk of default escalates notably with the increase in hurricane categories, especially moving from category two to three.
  • Heavy Rains and Flood Risks: Heavy rainfall in flood-prone areas also shows a substantial impact on default risks. Interestingly, such conditions discourage prepayment of mortgages, as borrowers may prefer to retain the option to default if insurance fails to cover disaster damages.
  • Climate Change Projections: By employing the First Street flood model projections for 2050, the study anticipates a systematic increase in mortgage risks due to climate change. This increase varies based on different scenarios of extreme weather events.

The findings of this study underscore the importance of integrating climate-related risks into mortgage risk assessment. As the world grapples with the impacts of climate change, this research provides valuable insights for risk managers and financial institutions to better prepare for and mitigate these emerging risks. The study not only confirms previous beliefs about the impact of weather extremes on mortgages but also offers precise quantification of these effects, emphasizing the need for climate-adjusted credit risk assessment in the face of changing environmental conditions.

Hot planet made deadly South African floods twice as likely: climate scientists

Flash flood in Palapye, Central District, Botswana. Heavy rain caused a small dam to burst on the Lotsane River, which flows through the village. The mud walls of traditionally built houses dissolved like icing sugar, leaving just the roofs: the breeze-block buildings in the background survived intact. A young goat has become entangled in a wire fence and drowned, but it's believed no human lives were lost. Taken 1995 on film. Author: JackyR, CC BY-SA 3.0
Flash flood in Palapye, Central District, Botswana. Heavy rain caused a small dam to burst on the Lotsane River, which flows through the village. The mud walls of traditionally built houses dissolved like icing sugar, leaving just the roofs: the breeze-block buildings in the background survived intact. A young goat has become entangled in a wire fence and drowned, but it’s believed no human lives were lost. Taken 1995 on film. Author: JackyR, CC BY-SA 3.0.

“We need to drastically reduce greenhouse gas emissions and adapt to a new reality where floods and heatwaves are more intense and damaging,” said a co-author of the study.

“If we do not reduce emissions and keep global temperatures below 1.5°C, many extreme weather events will become increasingly destructive.”

By Jessica CorbettCommon Dreams (CC BY-NC-ND 3.0).

Intense rainfall that led to deadly flooding and landslides in South Africa last month was made twice as likely by the human-caused climate crisis, a team of scientists revealed Friday, pointing to the findings as proof of the need to swiftly and significantly curb planet-heating emissions.

Experts at the World Weather Attribution (WWA) initiative found that heavy rainfall episodes like the one in April that left at least 435 people dead can be expected about once every 20 years versus the once every 40 years it would be without humanity warming the planet.

WWA climatologists warn that without successful efforts to dramatically reduce emissions, the frequency and intensity of such extreme events will increase as the global temperature does.

“If we do not reduce emissions and keep global temperatures below 1.5°C, many extreme weather events will become increasingly destructive,” said study co-author Izidine Pinto of the Climate System Analysis Group at the University of Cape Town. “We need to drastically reduce greenhouse gas emissions and adapt to a new reality where floods and heatwaves are more intense and damaging.”

During an April speech announcing a disaster declaration, South African President Cyril Ramaphosa said that communities in the eastern part of the country were “devastated by catastrophic flooding,” noting that it “caused extensive damage to houses, businesses, roads, bridges and water, electricity, rail, and telecommunications infrastructure.”

Ramaphosa also highlighted the death toll, sharing that when he and other officials visited affected families, “they told us heart-breaking stories about children, mothers, fathers, sisters, brothers, grandparents, and neighbors being swept away as their homes crumbled under the pressure of the flood waters.”

The city of Durban was hit particularly hard and its port—the largest in Africa—had to suspend operations because of the extreme weather.

Friederike Otto from Imperial College London, who leads WWA and co-authored the new study, pointed out that “most people who died in the floods lived in informal settlements, so again we are seeing how climate change disproportionately impacts the most vulnerable people.”

“However, the flooding of the Port of Durban, where African minerals and crops are shipped worldwide, is also a reminder that there are no borders for climate impacts,” she added. “What happens in one place can have substantial consequences elsewhere.

In addition to the chances of an event such as the mid-April rain disaster doubling due to human-induced climate change, the WWA team found that “the intensity of the current event has increased by 4-8%.”

The New York Times noted that “the work has yet to be peer-reviewed or published, but it uses methods that have been reviewed previously” and “the finding that the likelihood of such an extreme rain event has increased with global warming is consistent with many other studies of individual events and broader trends.”

WWA’s previous work includes a review of last year’s fatal heatwave in the Pacific Northwest, which the scientists concluded would have been “virtually impossible” in a world without the climate emergency.

“Our results provide a strong warning,” that WWA analysis said. “Our rapidly warming climate is bringing us into uncharted territory that has significant consequences for health, well-being, and livelihoods.”