Science in action: Powered by people, guided by data

Two people walk across rocks near a swollen, fast-flowing river with houses and green hills in the background. — All photos by Prakash Chandra Timilsena

In the early hours of July 15, 2024, Prem Bahadur Danuwar’s phone wouldn’t stop ringing. When he finally answered, a familiar voice urged him: “A flood is coming. It’s extremely dangerous. Leave your home without delay!”. Minutes later, the river tore through his village in central Nepal, sweeping away his house, farmland, and everything he’d built.

But Prem and his wife were safe. A four-minute warning from Kedar Karki, a community leader upstream, gave them just enough time to reach higher ground.

Stories like this show how lifesaving it can be when people have the right information at the right moment. In the Indrawati river basin, where floods are growing fiercer and more unpredictable, communities now face these threats with greater confidence, stronger networks, and better tools. At the heart of this change is a system built not just on data, but on trust, relationships and local knowledge.

Recently, experts in helping people prepare for disasters from Practical Action joined with others in the field to discuss what should be done to improve warning systems.

As climate change increases and extreme weather causes more landslides and floods, droughts and prolonged periods of heat.

Practical Action’s experts are calling on regional and national decision makers to invest in better systems, backed by support from local communities, who should be made part of preparation and evacuation efforts.

This story from Nepal, which is mirrored by similar work across Asia and Latin America, illustrates how things can, and should, improve if the right decisions are made.

From devastating floods to local solutions

Three years earlier, in June 2021, intense rainfall triggered floods and landslides in the Indrawati basin. The disaster claimed 5 lives, left 20 people missing, and destroyed bridges, homes, and water systems. Hundreds of families were displaced. These weren’t isolated events. Yearly, the monsoon season brings new risks to the communities living along the Melamchi, Yangri, and Larke rivers.

To support communities in preparing for and reducing the risk of future disasters, Practical Action worked with local partners and government agencies to develop a flood early warning system that reflects how people live, communicate, and organise themselves.

The system combines technology and data, via automatic river and rainfall sensors, with citizen science. Thanks to training and community leadership, local people now observe and share risk information, and then act on it.

This work gives nearly 60,000 people training and alerts and reaches more than 120,000 others through community networks and shared tools. Though funding cuts shortened the project, it came remarkably close to its goals.

Collaboration that saves lives

Prem’s warning came from someone he trusted: Kedar Karki, chair of Melamchi’s Community Disaster Management Committee. Both men served on the committee, working to protect their villages. When Kedar saw the flood hit his own upstream community, he immediately called Prem downstream.

“I feel like I am living my second life,” Prem said later. “The early warning gave me just enough time to reach safety. I owe my life to the people who sent those messages, even while their own homes were being flooded.”

This kind of neighbour-to-neighbour communication is the system’s backbone. In emergencies, it is often people in the next village who make the difference.

Two people work in a muddy outdoor area, using shovels to dig into the ground near a makeshift tent covered with white tarps. — Pictured: Prem Bahadur Danuwar at the flood aftermath

How does the early warning system work?

To be effective, early warning systems need four strong pillars:

Understanding risk: Identifying the communities most vulnerable to floods and mapping those risks
Monitoring and detection: Using automatic rainfall and river sensors to track real-time conditions
Communication: Making sure alerts reach the right people, in the right way, at the right time
Preparedness and response: Training people to understand the alerts and act on them quickly

Previously, government hydrology stations here were manual, sending data by post monthly. Forecasts were often late or no longer reliable. Now, upgraded stations send real-time data to the Department of Hydrology and Meteorology every 20 minutes, enabling timely forecasts and automated SMS alerts. But technology alone isn’t enough: science must reach people in ways they can use.

Alert and prepared to act

One morning in August 2024, Gyanu Giri was getting ready for her day when her phone buzzed. A text warned that the Melamchi River had crossed the danger mark 14km upstream. The flood was heading her way. As part of the local search-and-rescue team, Gyanu knew what to do. She alerted neighbours and helped them evacuate. Simultaneously, trained volunteers shared ground updates via a community Facebook group.

Thanks to these combined efforts, Gyanu’s community reached higher ground safely. Their homes were spared, but they were ready. Gyanu had a go-bag packed with documents and supplies. “We stay prepared, vigilant and informed,” she said.

A woman in a red patterned dress sits on a log outdoors near a river, with stacked firewood and greenery in the background. — Pictured: Gyanu Giri

Fighting fear with information

In Gyalthum Bazar, Durga Acharya is helping her family manage more than just the fear of another flood. After their home was damaged in the 2021 disaster, her nine-year-old daughter grew increasingly anxious every monsoon season.

Durga, a development worker and trained early warning coordinator, now tracks the latest data from river sensors and rainfall monitors. She uses this information to reassure her daughter, explaining what is happening and when it is safe. It gives the family peace of mind.

She has also taken part in multiple training programmes, learning how to communicate risk clearly and calmly. Durga now goes door to door in her neighbourhood, checking on vulnerable families and making sure no one is left uninformed.

People at the centre, science at their side

As the climate crisis accelerates, disasters like floods and landslides are becoming more frequent and severe. But communities are not helpless. When they have access to the right tools, knowledge and support, they lead the way in protecting themselves and each other.

The Indrawati basin’s early warning system proves this. It’s not just technology. It’s about people. It is about trust, relationships, and local leadership. Neighbours look out for each other. Women lead search and rescue efforts. Children learn how to stay safe. When the last monsoon came, not a single life was lost.

This is what science in action looks like when communities lead it, and organisations like Practical Action can support them. To keep this progress going, early warning systems must be maintained, adapted, and rooted in the daily lives of the people they serve. It is a shared responsibility and a shared success.

The project ‘Community Centric Early Warning System for reducing risk of hydro-meteorological hazards in Bagmati Province’ aimed to reduce the damage caused by floods and landslides in the Melamchi-Indrawati watershed. It ran from August 2022 to June 2025, but was cut short by 4 months due to USAID funding cuts. Despite this setback, the project came close to meeting its targets, aiming to directly support nearly 60,000 people and indirectly reach over 130,000 more.

Dharam R. Uprety, Disaster Risk Reduction Lead at Practical Action Nepal, states:

“This approach saves lives, but as climate change hits harder, it must go further — and fast. Every community facing flood risks deserve the same protection: timely warnings, trusted networks, and the power to act.
“At Practical Action, we have examples that show what can be done in a cost-effective way. I call upon decision makers around the world to help us scale this success. Together, we can bring life-saving resilience to every vulnerable person and community.”, Dharam R. Uprety, Disaster Risk Reduction Lead in Practical Action in Nepal.

Learn more about our work in Nepal.

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