Shimla: The north Indian hill state of Himachal Pradesh has identified 67 vulnerable glacial lakes, including several located in remote and high-altitude areas, and is working towards establishing early warning systems for four of the most vulnerable lakes in Kinnaur and Lahaul-Spiti, Pushpinder Rana, Special Secretary, Disaster Management, Himachal Pradesh government, said on Saturday.
The state is monitoring the identified lakes through satellite imagery and other scientific data to detect changes that could increase the risk of glacial lake outburst floods (GLOFs), while technical solutions are being explored to install sensors and transmit real-time information from locations where conventional communication networks are unavailable.
Speaking in Shimla, Rana said the identification of a large number of vulnerable glacial lakes was a matter of concern, particularly as recent Himalayan disasters have demonstrated that major incidents can develop without conventional warning indicators such as intense rainfall.
"Number bada hai, chinta ka vishay toh hai hi (The figure is huge, it's a matter of concern). At the State Centre for Climate Change, we have identified 67 such lakes which are above 10 hectares in area. We are analysing them through satellite and other data to see whether any such situation is developing in them," he said.
Glacial lake outburst floods occur when water accumulated in or around a glacial lake is suddenly released, potentially sending large volumes of water downstream. Such events can cause flash floods, damage infrastructure and threaten settlements located along downstream valleys.
Rana said recent incidents in the Himalayan region had highlighted the difficulty of predicting such events solely on the basis of rainfall forecasts.
He said the state was therefore seeking technological solutions that could allow vulnerable lakes to be monitored continuously, particularly those situated in inaccessible terrain.
"Until we find an innovative way to move forward on this, we will not be able to take effective steps regarding them," Rana said.
Rana said Himachal Pradesh had submitted a proposal to the National Disaster Management Authority (NDMA) for establishing early warning systems for vulnerable glacial lakes.
He said four lakes in Kinnaur and Lahaul-Spiti had been taken up for work under the National Landslide Mitigation Programme, with efforts focused on strengthening monitoring and early-warning capabilities.
The lakes include Parchu Lake and vulnerable locations in the Sangla-Kinnaur region, besides sites in Lahaul-Spiti.
The proposed systems are intended to detect potentially dangerous changes in lake conditions and communicate warnings to authorities and downstream populations.
However, Rana said installation of such systems at high-altitude locations remained a major technological challenge.
"The early warning system is a technical challenge. The problem is that these locations are in very remote areas where there is no network connectivity. Where will the sensors be installed, how will they be installed and how will the data be transferred? These are the challenges," he said.
The state is working with the Centre for Development of Advanced Computing (C-DAC) to develop technological solutions for these challenges.
Rana said once final approval is received from NDMA, the state would begin installing an early warning system at Dipang Ghat.
Alongside early warning systems, the government is undertaking High Flood Level (HFL) marking in downstream areas that could potentially be affected by a sudden release of water.
"The High Flood Level marking in the downstream areas that could be affected is also being taken up at Dipang Ghat. The process is underway," Rana said.
Rana said regular monitoring and community awareness would form an important part of the preparedness strategy around vulnerable lakes.
"The idea is that we will move forward towards an early warning system. The High Flood Level marking and regular monitoring will also be deployed at such locations," he said.
The state's approach is also linked to scientific studies of Himalayan glaciers and glacial lakes using satellite-based observations.
Experts studying the Himalayan region have increasingly relied on remote sensing and satellite imagery to map changes in glaciers and lakes, particularly because many high-altitude locations are difficult or dangerous to access on the ground.
Satellite datasets have enabled researchers to compare glacier extent and lake formation across different Himalayan basins over time. Studies involving Himachal Pradesh have examined basins including the Sutlej and Spiti and have documented changes in glacier areas and the number and size of glacial lakes.
The use of higher-resolution satellite imagery has also improved the ability to identify smaller water bodies and track changes in their extent.
Such scientific monitoring is important because an increase in the number or size of glacial lakes, changes in surrounding glaciers, unstable moraine dams and other physical changes can indicate evolving risks, although individual lakes require site-specific assessment before being classified as an imminent GLOF threat.
Rana said satellite data would therefore remain an important component of the state's monitoring strategy.
Rana said GLOF risks could not be addressed by Himachal Pradesh or India in isolation because the Himalayan river systems and glacial landscapes extend across international boundaries.
"There are around 1,000 such lakes within the Indian side of the border, and to understand what is happening and how it is happening, we definitely need international knowledge and exchange," he said.
He stressed the importance of sharing information about developments in high-altitude areas and upstream river systems, particularly where changes could have consequences for downstream populations.
The issue assumes added importance for Himachal Pradesh because several major river systems originate in or pass through high-altitude Himalayan terrain.
Rana said the state was also strengthening its broader disaster information and response mechanism.
The emergency helpline 1077 is available for reporting disasters and potential hazards, while Emergency Response Centres at the district and state levels remain operational round the clock.
He said information received from different sources, including the India Meteorological Department, is assessed and verified before authorities take action.
With Himachal Pradesh increasingly exposed to GLOFs, flash floods, cloudbursts, landslides and other climate- and weather-related hazards, officials say combining satellite surveillance, scientific assessment, ground-level monitoring, early warning systems, HFL mapping and rapid emergency response will be critical to reducing risks in vulnerable Himalayan valleys.
