Subscribe
Sissu, located on the banks of the Chandra River, is the first major stop in Lahaul-Spiti after exiting the Atal Tunnel. Until a few years ago, the village was known mainly for its quiet mountain life, farming and animal husbandry. Now, it is busy with tourists. The tourism industry has grown rapidly since the Atal Tunnel opened in October 2020.
Around 2,000 vehicles travel through the tunnel daily towards Sissu and Manali. During the peak tourist season, this rises to around 5,000. Tourists go boating in the artificial lake built along the river, young people zipline, off-road vehicles race through the area, and hundreds of visitors stop by every day.
But behind this beauty, an unseen danger is unsettling the people of Sissu. Whenever it rains, Rita Katoch wakes several times at night to look outside.
About 11 kilometres from her home, a Himalayan lake is growing larger every year. “It’s okay when the weather is clear,” says Katoch. “But when the rains start and don’t stop, it’s scary. But this is our home, and I don’t want to leave it.”
Situated at an altitude of 4,068m among the snow-capped peaks above Sissu, Ghepang Ghat glacial lake, known locally as Ghepan Lake, is steadily expanding. Its rising water level and growing size have become a warning sign for people living downstream.
The National Disaster Management Authority has classified the lake as “highly vulnerable”. Scientists fear that, if a glacial lake outburst flood occurs, Sissu will be the first and most vulnerable village in its path.
Named after Ghepan, the protector deity of Lahaul, the lake has deep ties to local culture and faith. Trekkers still pay homage at the Ghepan Devta Temple in Sissu before heading towards it. But the lake’s name is no longer invoked only in relation to religion or trekking. It has become part of villagers’ everyday conversations, worries and fears for the future.
According to a risk assessment report by the National Remote Sensing Centre (NRSC), Hyderabad, Sissu is the village most vulnerable to a lake burst. The report assessed eight possible lake burst scenarios and placed Sissu in the red zone in all eight. It says the steep slope between the lake and the village could accelerate the flow of water and debris. After Sissu, Goshal and Tandi villages are also at high risk.
In a worst-case scenario, floodwaters could reach Sissu within just 21 minutes of a lake burst. Estimates suggest water speeds of up to 43 kilometres per hour and depths of up to 20 metres.
Scientists say that, in the event of a flood, large amounts of debris, rocks and boulders would come down with the water. Such a flood could affect 34 settlements, 204 hectares of cultivable land, 57 bridges and 106 km of road.
The Manali-Leh National Highway, the Atal Tunnel and tourism-related infrastructure would also be at risk. According to the report, the impact would not be limited to Himachal Pradesh, but could be felt as far as Jammu and Kashmir through the Chenab River.
The NRSC has created maps of potential flood zones using satellite imagery and modelling. These maps identify buildings, farms, bridges and power projects. But for villagers, the threat is no longer just a scientific document.
The biggest concern about Ghepan Lake is not only its expanding size, but also the apparent gap between years of scientific warnings, satellite monitoring and detailed risk assessment reports, and preparedness on the ground.
There is currently no early warning system installed on the lake.
Several organisations, including the NDMA, the Central Water Commission and the National Centre for Polar and Ocean Research (NCPOR), are working together. A pilot system developed by the Centre for Development of Advanced Computing (C-DAC) has been installed on the artificial lake at Sissu, but it is still in the testing phase.
The system, equipped with sensors to measure temperature, wind, pressure and rainfall, as well as cameras and a satellite-based alert mechanism, is being tested just downstream from Sissu village.
Sissu and surrounding areas also lack public warning boards, siren systems, clear evacuation routes and real-time alert mechanisms that could immediately alert people in the event of a disaster.
The people living in Sissu are learning to live with this danger. Alongside fear, there is also a belief that nothing may happen.
Jitendra Kumar, who runs activities such as ziplining and boating for tourists along the Chandra River and earns his living from tourism, says: “In the last year or two, the rumour that the lake could burst at any time has become widespread. The fear persists, but we have to work. We have no other option.”
His words reflect both anxiety and helplessness. Tourism has created employment opportunities for young people in Sissu. Many have taken up farming alongside homestays, cafes and adventure activities. But that same tourism now appears to be increasing pressure on the climate and environment.
Kamal, also from Sissu, visited Ghepan Lake in 2024 and is less concerned about the danger. “The lake is very high up,” he says. “It’s not easy to reach it.”
He adds: “I saw water continuously flowing out of the lake and down into the Sissu drain. I don’t think the lake will burst.”
There are two schools of thought locally: on one side are the scientific warnings, and on the other is the lived experience of people who have spent decades in the region.
Experts consider the threat serious. Ghepan Lake is a moraine-dammed glacial lake, which means it formed behind a natural dam of rocks, sand and debris deposited by the retreating glacier. Such dams are considered vulnerable.
Heavy rain, landslides, avalanches, or large chunks of glacier breaking off and falling into the lake could suddenly breach the dam. In such a situation, the water would not drain slowly, but rush down in a rapid flood carrying debris and rocks.
According to the NRSC report, Ghepan Lake covered 36.49 hectares in 1989. By 2022, it had expanded to 101.30 hectares. This means the lake has nearly tripled in size in three decades.
A study, Mass balance of lake terminating Gepang Gath glacier (western Himalaya, India) and the role of glacier–lake interactions, published in the Journal of Glaciology on April 21, 2025, found that the Ghepan Glacier’s mass balance remained consistently negative — minus 0.90 metres of water equivalent per year — between 2015 and 2023. Put simply, more ice is melting each year than is accumulating.
The study shows that since 1962, the Ghepan Glacier has retreated by about 2.76 kilometre and is shrinking at an average rate of 53 metres a year.
Bhanu Pratap, co-author of the study and a glaciologist at NCPOR, says: “The temperature in the Himalayan regions has increased rapidly in the last 30-40 years. Where there used to be more snowfall, now rainfall is increasing. Rain melts the glaciers much faster than snow. This is a cumulative process, which once started, continues to increase.”
According to Pratap, not only rising temperatures but also changing rainfall patterns are driving glacier shrinkage. “Earlier, the higher altitudes received mostly snow. Now, it’s raining there. Rain directly impacts the glacier surface and accelerates melting. This effect is being felt not just on one glacier, but across the entire Himalayan region,” he says.
Experts say the melting glacier and expanding lake are reinforcing each other. As the lake’s water level rises, it melts the underside of the glacier faster. This causes large chunks of ice to break off and fall into the lake, further increasing its size.
Meteorological Department data shows that weather in Lahaul-Spiti is changing rapidly. A comparison of average temperature and rainfall between 1971-2000 and recent years shows that March and April have become significantly warmer.
This year, temperatures reached 24.8°C in April, compared with earlier years when peak temperatures were usually seen in May or June. February and March are also much warmer than before. The impact is not limited to glaciers. Local people are also seeing changes in agriculture, water sources and snowfall patterns. Kamal says: “Since the tunnel opened, there’s less snow here. Winters used to be longer. The weather has changed.”
Pointing to trees at the village entrance, he adds: “The leaves used to turn green and yellow, but now they turn black and fall off.”
Scientists avoid directly linking these changes to tourism or vehicles alone, but say increased activity at the local level adds environmental pressure.
“I came here in 1987 during the Chota Shigri Glacier expedition. Back then, there was barely a guest house in Sissu. For months, no one would be seen. Now, it’s overcrowded,” says Anil Kulkarni, visiting professor and senior glaciologist at the Indian Institute of Science, Bengaluru.
Kulkarni says the impact of human activity in fragile regions such as the Himalayas can be severe in the long term. Dust kicked up by vehicles settles on snow surfaces, reducing their reflectivity and causing them to absorb more heat. As a result, melting increases.
He says the concern is not only glacier melt, but also rapid construction. If a lake bursts, it will not bring down just water, but also debris, rocks and trees. Such events have a cascading effect, multiplying the devastation.
The story of Ghepan Lake is not an isolated one. It reflects wider changes taking place across the Himalayas. According to the Nepal-based International Centre for Integrated Mountain Development, about 12 per cent of glacier area in the Hindu Kush Himalayan region was lost between 1990 and 2020. Glacier area in the western Himalayas has also shrunk from 8,964 sq km to 7,878 sq km.
In the Chenab sub-basin, where Ghepan Lake is located, large glaciers are melting and fragmenting into smaller pieces, creating a growing number of new lakes. These changes pose a significant threat to communities living in the Himalayan foothills.
According to the World Glacier Monitoring Service’s 2025 projections, the world’s glaciers, excluding Greenland and Antarctica, will lose 408 gigatonnes of ice by 2025. Lead author Michael Zemp says the amount of ice lost could fill five Olympic-sized swimming pools every second. According to Zemp, the Himalayas, along with Russia and Alaska, are among the regions where glaciers are rapidly losing mass.
According to the Central Water Commission’s 2024 report, the total area of glacial lakes in India has increased by about 29 per cent compared with 2011. Meanwhile, the Himachal Pradesh State Climate Change Centre’s Annual Report 2024-25 says the state had 805 glacial lakes in 2016, rising to 1,619 by 2022. Their number has almost doubled in six years.
Snow cover in the state is also decreasing. In the winter of 2023-24, snow cover in Himachal Pradesh was recorded at 13 per cent less than the previous year.
People in Sissu and surrounding villages are aware of the danger posed by the lake. The movement of scientists, researchers and administrative teams has increased in the villages. Discussions are also taking place on social media and WhatsApp groups.
Vipin, from Goshal village, says: “People know that there is a lake above and that there is danger. Researchers often come here.”
Rajiv, the head of Sissu panchayat, says the administration conducts mock drills every year and has identified safe locations. But another fear also exists among villagers: displacement. Although they do not discuss it openly, he recalls the example of Lindur village, where families affected by land subsidence are still awaiting permanent rehabilitation.
“What will happen to us if the water ever washes everything away?” This question remains unspoken among many villagers.
Nepal’s Tso Rolpa Lake in the Hindu Kush Himalayas is often cited as a successful example of flood management in the region. Early warning systems and regular mock drills helped people to be safely evacuated during a flood in 2016. At Ghepan Lake, however, similar systems are not yet in place to reduce potential damage.
Thousands of tourists who visit Sissu return with photographs of the lake, river and snow-capped mountains. Most have no idea that behind these mountains, a lake is growing larger every year.
Rita still dreads every rain. Jitendra goes to work every day. Kamal still believes nothing will happen. But the changing climate has left a lasting unease in this quiet Himalayan village — a fear that is invisible for now, but constantly growing.
Raman Kant is a mentee at the Asian College of Journalism’s Climate Change Media Hub, supported by Interlink Academy, Germany.