Melting Glaciers, Fragile Slopes, Human Hubris: What Led To Uttarakhand's Tragedy

Five dead, dozens missing. Was it a cloudburst or a glacial lake outburst? Experts say the Uttarakhand flash floods reflect the escalating impact of climate change on the Himalayas, where shifting monsoon patterns, glacier melt, and unchecked construction converge to amplify such extreme weather risks.

Climate Change Fuels Extreme Weather

Scientists attribute the increasing frequency and intensity of such events to rising temperatures and humidity. "With the axis of the monsoon trough running through the foothills of the Himalayas, we had already predicted a red alert for Uttarakhand," said Mahesh Palawat, Vice President of Meteorology and Climate Change at Skymet Weather. "While the affected region is prone to cloudbursts, such a turn of events is due to the climate change-led rise in temperatures.

A huge influx of moisture from the abnormal warming of oceans increases the capacity of the air to hold more water vapour. The Himalayas act as barriers, which give rise to vertically developed convective clouds, known as Cumulonimbus clouds.

Sometimes, the vertical height of such clouds might even reach up to 50,000 feet. These clouds are like a column of water, which, when restricted due to topography like the mountains, can lead to the release of water over a smaller area in a shorter duration."

A recent study highlights how spring land heating in the Middle East, warming at twice the global average, is pushing south-westerly winds northward, intensifying rainfall over northwest India and Pakistan.

"The rapid warming over the Middle East and the Mediterranean is a signature of global warming," said Dr Raghu Murtugudde, Climate Scientist and Emeritus Professor at the University of Maryland. 

"This regional warming has been pulling the southwestern winds northward over the Arabian Sea. There is excess moisture being pumped into the Himalayan foothills. Because of this northward shift of the south-westerly winds, we might end up with more heavy rainfall events all the way into Himachal Pradesh and Leh Ladakh before the season is over."

This shift, driven by the low-level jet (LLJ) transporting moisture from the Arabian Sea, is amplifying atmospheric instability, leading to unprecedented rainfall in regions like Uttarakhand. The study notes a 46% increase in intensified rainfall over northwest India and Pakistan from 1979 to 2022, a trend likely to persist.

Glacier Melt and Landslide Risks

The Himalayas are warming at three times the global average, accelerating glacier melt and destabilising mountain slopes.

According to the Ministry of Earth Sciences (2023), Hindu Kush Himalayan glaciers are retreating at an average rate of 14.9 ± 15.1 meters per year, with variations across basins: 12.7 ± 13.2 meters in the Indus, 15.5 ± 14.4 meters in the Ganga, and 20.2 ± 19.7 meters in the Brahmaputra. Karakoram glaciers remain relatively stable, but in the Garhwal Himalaya, retreat rates vary significantly, with Dokriani Glacier receding at 15-20 meters annually and Chorabari Glacier at 9-11 meters.

This rapid melt is filling glacial lakes, increasing the risk of overflow and downstream flooding. A 2019-2018 study recorded 127 large glacier-related landslides across the Karakoram, Pamirs, Western Himalayas, and Hindu Kush, highlighting how glacier thinning is destabilising slopes. The IPCC's special report on the cryosphere notes that permafrost thaw and glacier retreat are further weakening infrastructure integrity, exacerbating landslide risks.

Unplanned Development Amplifies Vulnerability

As the ghosts of Kedarnath 2013 and Rishiganga 2021 loom large, why have we failed to curb rampant, unplanned development in this fragile region, inviting nature's wrath again?

Unregulated infrastructure projects-roads, tunnels, hydropower plants, and hotels-in ecologically fragile zones are worsening the situation. 

"The role of global warming is already established in the rise of extreme weather events," said Professor YP Sundriyal, Adjunct Faculty of Geology at Doon University, Uttarakhand.

Ecologically, the Himalayas are very fragile as they are the youngest mountain range in the world. When such torrential rainfall occurs over hill slopes, it becomes more dangerous as debris flow leads to erosion due to landslides, making flash floods more powerful and disastrous."

Urgent Need for Monitoring and Adaptation

Experts are sounding the alarm for immediate action. Rainfall extremes in high-elevation areas are amplified by 15% per degree of warming-double the rate predicted by atmospheric theory-making early warning systems, floodplain zoning, and community evacuation plans critical. "With per degree centigrade warming, the extreme precipitation increases by seven to eight percent," said Dr Subimal Ghosh, Institute Chair Professor at IIT Mumbai. 

"We should have early warning systems and better adaptation designs, which are very much needed at the moment. It is very important to have floodplain zoning and to identify the regions that are extremely prone to flooding. If there is an early warning of extreme precipitation, immediately carry out evacuation from the region under the extreme flood zone."

Professor Anjal Prakash, Research Director at the Bharti Institute of Public Policy, emphasised the need for climate-resilient infrastructure. 

"Such devastating events in Uttarkashi and other hilly regions highlight the increasing frequency of cloudbursts and flash floods driven by climate change," he said. 

"India is not doing enough to develop climate-resilient infrastructure that can withstand these extreme weather events. Enhanced surveillance and early warning systems are vital in addressing the increasing frequency of extreme weather events. Automatic Weather Stations (AWS) play a vital role by providing real-time data from the Himalayas, especially in their upper reaches."