The sun was shining brightly on a hot mid-afternoon in late June when the residents of Lindur, a village perched at an altitude of 3,328 meters in Lahaul, Himachal Pradesh, heard the loud sound of rushing water. Jahlma Nallah was flooding again! “The sun was so hot, I knew Jahlma will flood soon,” noted Jagdish prophetically, a resident of Lindur whose home and fields are adjacent to Jahlma Nallah, a glacial stream that comes down from the Pir Panjal range to meet the Chenab river below. In a matter of minutes, the usually thinly flowing stream transformed into a terrifying, debris-laden torrent. Brown sludge raced towards the Chenab and nearly blocked the river with its brute force. A month earlier, repeated flooding had led to the collapse of the only bridge across the nallah connecting hundreds of mountain villages to Manali and the world beyond. The flooding occurs in the afternoon without rain, snowfall or even cloud cover. While the Himalayas have been repeatedly inundated by floods and landslides as soon as monsoon starts in the past years, Jahlma Nallah’s flooding in the absence of rain is a considerably more curious and less understood phenomenon, recurring for the last five years. Residents recount how the bridge’s collapse each year heightens hardshipsLindur’s drinking and irrigation water comes from the glacial melt that flows through Jahlma Nallah. However during May and June, instead of being a source of sustenance and life, the nallah threatens the land and livelihoods of people in Lindur and other villages downstream like Jahlma, Jasrath and Jobrang. “Every year, one month of connectivity is being lost to the floods of Jahlma Nallah and its only increasing,” said Govind Phurpa, whose village Phura is located on the banks of the nallah. The bridge across Jahlma Nallah, part of the Sansari-Kilar-Thirot-Tandi (SKTT) road, connects several villages to markets in Manali through the Atal Tunnel. Collapsed section of an apple orchard in Lindur. Photo: Abhay Kanvinde. When flooding destroys the bridge, like it did this June, the consequences extend beyond transportation, with remote farming communities suffering substantial economic losses. The region has only one farming season and the precious cauliflowers, lettuce and peas grown and harvested during this time wilt within days if they do not reach the market on time. Even villagers from Pangi Valley, more than 100 kms away from Jahlma Nallah, are affected by this disruption in connectivity and have asked the Border Road Organisation (BRO) to repair the Jahlma bridge to prevent losses to their harvests.The bridge collapsed in the last week of May. “It has been hammered by floods the last five years. This year there were landslides from Jahlma repeatedly. The foundations just gave way,” said Rahul Rajput from Lindur.Now, the backwater and debris of Jahlma is threatening the Jobrang bridge on the Chandrabhaga (Chenab) itself. “The administration says that it will be July 20 at the minimum for the bridge to open. This will mean immense losses to the farmers. We built a Kuhl (irrigation channel) from the Jahlma Nallah just last year to irrigate our fields. I can only see rubble in its place now,” Rahul added. “Lines of trucks and tempos laden with vegetables are stranded on the banks of Jahlma Nallah. In the absence of a bridge, we were using a zipline installed by the administration to cross the nallah. It was very scary,” said Jagdish, “Every year the nallah bed gets about 5 metres deeper after the floods.” It is not just the local economy, but also the everyday socio-cultural life in the region that gets disrupted each year. Govind recounted how a family of newlyweds and their guests had to wade through debris to cross the nallah. The elderly and sick residents are the worst impacted, disruptions bringing more hardships. According to Govind, an elderly woman who was severely ill had to be placed inside the arm of a JCB excavator to be carried across the nallah.Everyday life in the sinking Lindur village. Photo: Abhay Kanvinde.Administrators and politicians of Lahaul, like MLA Anuradha Rana, have attempted to address these problems through repeated road and bridge repairs, as well as discussions around compensation and relocation for Lindur residents. Each year, the BRO has been called to repair the bridge or the roads that were washed away by floods. However, the problem cannot be addressed through such quick-fix actions or responses.As Deputy Commissioner and chairperson of the State Disaster Management Authority Kiran Bhadana told reporters, the flooding of the rivers and streams in Himalayan valleys has intensified because of glacial melt. Why is Jahlma flooding?The diurnal floods of Jahlma Nallah under the scorching sun have become a dramatic, cyclic phenomenon that remains largely unrecorded and understudied. This cycle warrants urgent attention because it could point towards a looming ecological crisis in the Himalayas.Indeed, it is not just Jahlma that is flooding. More and more nallahs in the Himalayas are experiencing flooding during dry and hot summers. In 2025, South Asia Network on Dams, Rivers and People (SANDRP) listed multiple Himalayan nallahs that were most vulnerable to recurrent flooding and losses of life and property, requiring immediate attention and long-term approaches. As part of a collaborative ‘River Ethnographies’ research project examining the cryo-climatic changes in the Indus basin region, its impact on the Indus Waters Treaty and the everyday lived experiences of the people living along the main tributaries of the Indus river in India, we visited Lindur village in October 2024.Since then, we have been in regular communication with locals who share stories of the erratic and disruptive flooding of Jahlma Nallah. In July 2023, the nallah flooded catastrophically and ended up blocking the flow of the Chenab river by forming a landslide dam where it meets the river. Lindur village also suffered land subsidence and cracks developed in houses’ walls. “My old house is so cracked that I am building a new house in Lindur now. I know it might not be a long-term choice. But what option do I have? Banaye to bhi mushkil, na banaye to bhi mushkil (If we build a new house we suffer, if we don’t then also we suffer),” lamented Jagdish.After landslides, walls of homes in Lindur sustained cracks. Photo: Abhay Kanvinde.After prolonged protests, the administration appointed Indian Institute of Technology (IIT) Mandi and the Geological Survey of India (GSI) to examine the situation. The GSI study recommended sealing the cracks and relocating Lindur village. An IIT Mandi report revealed further insights. By extrapolating the changes in temperature, precipitation and soil temperatures in Lindur, the study found that the region is warming rapidly, while precipitation is becoming increasingly erratic, and permafrost – ground that remains frozen for more than two consecutive years – is melting. This, as per the report, could be the key reason behind the land subsidence in Lindur. Dericks P. Shukla, the lead author of the report, whose team has mapped more than 2,000 glacial lakes in the Himachal region, told one of the authors: “The exact causes behind the scale of flooding in Jahlma Nallah are not clear. In the absence of a glacial lake, the massive discharge of the flood is significant. One of the reasons could be thin debris covering the ice, which is not insulating enough, causing enhanced melting. One side of Jahlma Nallah has rock glaciers, the other has debris-covered glaciers. The villagers often climb up to monitor the cracks, and there are cracks as wide as two feet, with a depth of 20 feet near the glacier, they say.”The region is surrounded by rock glaciers, a mass of rocks and boulders holding onto an ice core that in turn is held together by networks of ice. Rock glaciers are an important storehouse of water and are supposed to be more climate-resilient than clean ice glaciers because of better insulation. However, the diurnal flooding of Jahlma Nallah each summer could indicate drastic climate-induced changes to the rock glacier. Shukla explained:“The study was published in the journal Nature reporting a high rate of (land) subsidence to the tune of 7.914 cm/year. We have analysed consistently increasing air and soil temperatures. Precipitation is changing entirely, with less snowfall in the early winters and more precipitation falling as rain and not snow. The slopes here are steep and made of meta-sedimentary rocks which are amenable to erosion. When water in the rock glaciers melts, it becomes a lubricant for this eroded debris and increases its speed over the steep slopes. But we need gauging stations [to measure] water and silt in the nallah to know what’s happening.”But there is no automated weather station in Jahlma Nallah or a discharge gauge station. Almost all the weather data used by the studies has been extrapolated from distant stations. The Nature report also underlines the “importance of more detailed studies into the interaction of climatic, geological and hydrological factors that drive permafrost thaw and land subsidence in the Indian Himalayas.”Bank cutting at Jahlma Nallah. Photo: Abhay Kanvinde. While accelerated melting of rock glaciers and permafrost is being increasingly reported the world over, none of the incidents show a catastrophic flooding like in Jahlma Nallah. There are no global parallels to explain what is happening in this remote part of the Indian Himalayas. Yet, there might be other places where a similar situation might be happening. Trilok Thakur from Pangi valleys told us: “Our elders have never seen nallahs flooding like this under the sun. Our connectivity is being lost even before the rains start.”This phenomenon is affecting thousands of rural mountain households, as well as local economy and ecology, and needs urgent and coordinated response from government agencies and scientific bodies. Currently, there is no dedicated effort to even understand it. Meanwhile, trucks and tempos laden with precious farm produce lay waiting on the banks of a Himalayan nallah that floods when the sun shines.Parineeta Dandekar is an associate coordinator with the South Asia Network on Dams, Rivers and People in Maharashtra. Madhumita Dutta is an associate professor of geography at the Ohio State University, USA.