People sits on a safer ground after another flash flood alert iin Nuwakot district, Nepal, on Friday. Photo by Narendra Shresth/EPA
Aug. 28 (UPI) — After Wednesday’s devastating glacier collapse in the Himalayas, scientists and geologists are warning that unstable conditions and the accelerating retreat of Andean ice sheets are exposing Chile, Argentina and Peru to the risk of catastrophic floods and mudslides.
The retreat of Andean glaciers has accelerated the formation of unstable lakes and exposed large slopes of loose rock that can collapse more easily as global temperatures rise, experts say.
Fast-moving floods and mudslides through mountain valleys could directly threaten drinking water supplies, energy projects and the lives of thousands of people living in vulnerable areas of the three countries.
The Himalayan disaster, which has left almost 600 people dead and more than 1,900 others missing, experts say that although monitoring and early-warning technologies exist, the speed and scale of glacial lake outburst floods, or GLOFs, such as the one in Nepal can make responding difficult.
“What happened in Nepal has already happened in Argentina,” Juan Pablo Milana, a researcher with Argentina’s National Scientific and Technical Research Council, told Infobae.
In November 2005, Laguna de los Erizos in San Juan province suddenly burst, releasing more than 1.1 billion cubic feet of water in just 67 minutes, Milana said. The flood traveled more than 155 miles, destroying crops and roads and isolating communities. No deaths were reported because the area was sparsely populated.
In Argentina, the areas at greatest risk are concentrated in Patagonia. One of the most critical sites currently under observation is the tourist town of El Chaltén, where instability on the slopes of Cerro Solo directly threatens Laguna Torre.
Lakes formed by the retreat of large ice masses, such as the Upsala Glacier, also pose a potential threat. In 2013, a collapse in the glacier’s channel generated a destructive wave in Onelli Bay.
Argentina’s Geological and Mining Survey and research teams from the University of Buenos Aires are responsible for monitoring the threats.
They combine satellite imagery used to update the National Glacier Inventory with projects to establish ground-based early-warning systems. Those systems are designed to use weather stations and hydrological sensors to detect changes in water levels and unusual slope movements in real time.
With more than 26,000 glaciers, Chile is among the countries most exposed to GLOFs worldwide, with risks divided between two distinct geographic areas.
The largest high-risk zone is concentrated in remote Chilean Patagonia, particularly the Aysén and Magallanes regions, where the rapid retreat of the Northern and Southern Patagonian Ice Fields has increased the formation of unstable lakes held back by fragile natural dams, although the region has a low population density.
Geographer Simón Inzunza told Chilean broadcaster T13 that the country has recorded GLOFs, particularly in Patagonia, as well as other emergencies associated with glacier melting and ice collapses.
In central Chile, watersheds are smaller but the risk is significant because of the high concentration of infrastructure, including hydroelectric plants, mining operations and drinking water systems serving millions of people.
Darío Ormeño, a geologist and professor at Andrés Bello University’s School of Earth Sciences, told BioBioChile radio that a mudslide is a real risk in Chile, although an event on the scale of the Nepal disaster is unlikely.
“Our glaciers are much smaller and do not have such an extreme elevation difference,” Ormeño said.
Chilean government agencies monitor glaciers using a national inventory updated with satellite imagery and radar. The tools allow authorities to measure the growth of glacial lakes and detect cracks in Andean slopes in an effort to issue early warnings before a disaster occurs.
Peru faces the highest risk in South America of disasters caused by GLOFs, with a history of deadly events and significant geographic vulnerability.
Paola Moschella, director of glacier research at Peru’s National Institute for Research on Glaciers and Mountain Ecosystems, or INAIGEM, told Exitosa radio that Peru has 528 lakes at risk of overflowing, including 58 considered high risk.
Unlike Patagonia and some high-altitude areas of Chile and Argentina, where glaciers are in remote valleys, entire cities and critical infrastructure in the Peruvian Andes, particularly in the Áncash region, lie directly along potential flood and mudslide routes.
Lake Palcacocha, in Peru’s Cordillera Blanca mountain range, is considered by scientists to be one of the world’s most critical cases because of its instability and proximity to the city of Huaraz, which has more than 120,000 residents.
The lake holds more than 599 million cubic feet of water and is fed by hanging glaciers that are susceptible to large avalanches as global temperatures rise.
If a large block of ice were to collapse into the lake, it could generate a massive wave capable of breaching its natural barriers and triggering a destructive flood that could reach urban areas in less than an hour.
The threat has a deadly historical precedent. In 1941, a similar outburst from the same lake destroyed about one-third of Huaraz and killed thousands of people.
Scientific monitoring in Peru has advanced significantly through the deployment of permanent personnel in high-altitude areas and the use of satellite surveillance systems.
Experts warn, however, that physical mitigation infrastructure installed in previous decades is outdated or insufficient to contain current water volumes.