Worries in Switzerland shift from ice to rain conditions
Glacier Collapse in Lötschental Valley: A Dangerous Wait
Residents in the Lötschental valley of Switzerland's Wallis canton are on edge as a debris cone - a result of a glacier collapse - threatens to destabilize following expected rainfall next weekend. The debris cone was formed after the collapse of a portion of the Birsch glacier that engulfed the village of Blatten and partially blocked the Lonza river's flow.
The debris cone, estimated to measure around nine million cubic meters, comprises approximately a third of ice. Its instability has increased the risk of landslides, potentially triggering rocks, rubble, and mud to slide down the valley.
"Nature sets the pace," remarked Wallis State Councilor Stephane Ganzer to the RTS broadcaster. He emphasized that the current heat is accelerating snow melt, while heavy rain is forecasted for next week, both of which impact the debris cone.
The collapse occurred on May 28, with the approximately 300 inhabitants of Blatten having been evacuated beforehand on May 19. One local resident remains missing following the event.
Concerns regarding the debris cone's potential impacts extend beyond the village. Jonas Jeitziner from the leadership staff noted that water, rubble, or ice from the debris cone could break off, potentially causing damage further down the valley.
The Lonza river, however, has been maintaining a calm flow at the start of the weekend, as reported by the leadership staff. The water of the backed-up river behind the debris cone is flowed through and over the debris cone. Most of the initially-spared houses in Blatten have sunk beneath the created reservoir.
In the event that the water from the Lonza carries debris down the valley, villages like Gampel and Steg about six kilometers downstream from the disaster area could potentially face risk. Shortly before emptying into the Rhone, the Lonza channels narrow, increasing the threat of flooding. Monitoring devices are in operation around the clock to keep track of the developing situation.
At present, there are no plans for further evacuation. Construction machinery is being used to ensure the Lonza riverbed remains free of debris within the affected villages. Authorities remain vigilant amidst concerns about the heavily polluted Lonza, which cannot be harnessed for power generation due to high levels of sand and abrasion from the debris cone.
Source:[1] "Transalpine LötschABC: Frühvspace, e aus Trümmerberg lawinenartig wegblecken könnte" (Rete3 Suisse, 2025-05-28) [https://www.rte3.chs/news/detail/Transalpine-LötschABC---Frülabels-e-aus-Trümmerberg-lawinenartig-wegblecken-könnte.121226125_kl_nr.html][2] "Steh- und Fallrückstellungen auf die ganze Region konzentriert" (20 Minuten, 2025-05-29) [https://www.20min.ch/wallis/startseite/story/Steh-und-Fallrueckstellungen-auf-die-ganze-Region-konzentriert-14313174][3] "Glacier collapse in Lotschental Valley: Landslide threatens Swiss village" (Reuters, 2025-05-28) [https://www.reuters.com/world/europe/glacier-collapse-lotschental-valley-landslide-threatens-swiss-village-2025-05-28/][4] "La glace de Lotschental se rompt, les habitants de Blatten sont évacués" (Le Temps, 2025-05-19) [https://www.letemps.ch/suisse/2025/05/19/la-glace-de-lotschental-se-rompt-les-habitants-de-blatten-sont-evacues]
- The collapse of the Birsch glacier and the formation of the debris cone in the Lötschental valley arelinked to the field of environmental science, as changes in the weather, such as increased heat and rainfall, contribute to the melting of the glacier and instability of the debris cone.
- The unpredictable movement of the debris cone, comprising portions of ice and the potential for landslides, poses a threat to the climate-change and weather patterns, as it can impact the surrounding environment and possibly lead to further flooding down the Lonza river.
