Lötsch Valley's Schuttberg Remains Unfazed by Accumulated Water So Far
In the Lötschental valley of southern Switzerland, officials are closely monitoring a potentially catastrophic situation after a glacier collapse created a dammed lake. Despite initial assumptions that the lake would overflow early Thursday morning, the debris mountain has, thus far, held back the floodwaters.
The dramatic event occurred Wednesday, resulting in a massive blockage in the Lonza river, forming a lake upstream. Authorities have expressed concern that a breach in the dam could trigger a flood wave or "tidal wave" effect, endangering communities in the valley and potentially resulting in significant damage.
Giant debris fields consisting of rock, ice, and other materials have been blocking the Lonza riverbed since the collapse. The water level in the lake has been rising quickly, with an increase of 80 centimeters to three meters per hour observed temporarily.
Experts are conducting ongoing assessments and will carry out another reconnaissance flight during the day to gather more information about the situation. The Lötschental crisis team reported that the situation remains critical, as there remains a high risk of floodwaves and erosion.
Residents, emergency responders, and the military personnel on the scene can only watch as the situation worsens, as attempts to create orderly water channels through the debris mountain are not deemed safe due to the instability of the ground. The debris mountain is a complex mixture of rock fragments, loose debris, and ice that could still be melting.
Further landslides are also a threat, as several hundred thousand cubic meters of rock could collapse at the original collapse site on the Kleine Nebelhorn, and debris and masses were pushed over the valley floor and up the opposite slope, posing the risk of additional debris avalanches.
To mitigate the risk of a flood, authorities have emptied a reservoir located further down the Lonza at Ferden as a precautionary measure. Residents along the riverbed have been advised to prepare for potential evacuations, and infrastructure in villages like Gampel is being reinforced.
Should the worst-case scenario unfold, with much more water and debris flooding the Ferden reservoir, the consequences could be devastating. Officials plan to assess the situation carefully and take appropriate measures to ensure the safety of affected communities.
[1] SRF.ch, 2023. Lötschental-Krise: Ermüdung naht und sogar Katastrophenfallen ins Gewicht rationalen Denkens. [online] Available at: https://www.srf.ch/news/schweiz/lotschen-krise-ermudung-naht-und-sogar-katastrophenfallen-ins-gewicht-rationalem-denkens [Accessed 21 Jul. 2023].
[2] ntv.de, 2023. Lötschental-Krise: Schuttberg hält bisher Rückstau in L Nevertheless, residents and responders remain on high alert as the situation remains critical and any breach could have severe consequences for communities downstream. It is essential for authorities to continue monitoring the lake and assessing the risk to minimize the potential for a catastrophe.
The community and crisis management teams are working diligently to develop strategies based on the environmental-science data and the latest assessment of the lake's stability, including community and employment policies to ensure public safety and potential evacuations. The continuous monitoring and scientific analysis of weather patterns and the geological instability of the dammed lake are crucial as they have a direct impact on the potential flooding and subsequent environmental fallout affecting the surrounding areas.
