Following a glacier's collapse in Switzerland, officials issue flood warnings for other regions. - Flood Alert Issued in Switzerland: Prepare for Potential Inundation
In the Lötschental valley of northern Switzerland, authorities have sounded the alarm following the collapse of the Birch glacier, which has left several towns at risk of flooding. On Thursday, approximately 16 residents were evacuated from Wiler and Kippel, with houses in Blatten, the initial target of the glacier's collapse, also facing destruction due to rising water levels of the Lonza river.
According to estimates by the cantonal authorities, an estimated three million cubic meters of rock and ice crumbled from the glacier on Wednesday, engulfing Blatten, which had been evacuated prior to the incident. As of Thursday, a 64-year-old man remained missing, according to authorities.
The potential threat of flooding extends beyond Blatten, with Wallis State Councillor Stéphane Ganzer warning of a "worst-case scenario" that could affect the villages of Gampel and Steg. However, this scenario is considered extremely unlikely at present. Christian Studer, a natural hazards expert, suggests a more likely outcome is the liquefaction of a significant portion of the mass due to high temperatures, which would flow down towards the valley.
The impending disaster was anticipated for several days, as increased activity at the glacier had been observed since the night of Tuesday to Wednesday. Blatten, home to about 300 residents, was evacuated the previous week.
Climate change-fueled glacier loss and shrinkage have compromised alpine communities and river systems for decades. In just the recent years 2022 and 2023, Swiss glaciers have lost 10 percent of their mass—equivalent to the mass lost between 1960 and 1990.
Similar disasters have occurred in the past, such as the major rockslide in the southern Swiss canton of Graubünden in August 2017. 3.1 million cubic meters of rock fell from the Piz Cengalo mountain near the Italian border, killing eight hikers. The village of Bondo was hit by hundreds of thousands of cubic meters of rock and mud, but fortunately, no residents were injured as the village had been evacuated prior to the incident.
The current incident underscores the interconnected risks that rising temperatures and glacier loss pose to alpine communities and river systems. Direct devastation in Blatten included the destruction of approximately 90% of the village, leaving hundreds of residents displaced. The disaster was a "cascading disaster," where warming temperatures, accelerated melt, and permafrost thaw weakened both the glacier and surrounding rock, leading to the catastrophic failure.
River obstruction and flood risk are significant concerns, with the debris from the landslide blocking the Lonza River, forming a 2 km-long dam that created a growing lake upstream. Authorities reported that the lake was swelling at a rate of 80 centimeters per hour, posing a serious risk of sudden outburst flooding if the dam were to break. Communities downstream, including Gampel and potentially the Rhone Valley, are at risk of catastrophic flooding should the dam give way.
Expert consensus points to rising temperatures and permafrost thaw as key drivers of the instability. Thawing permafrost beneath and around the glacier reduces cohesion in rock, increases water infiltration, and accelerates weathering and erosion, making the entire slope more prone to collapse. Experts warn that more frequent and severe glacier collapses and landslides are likely as global warming continues, leading to repeated cycles of instability, river obstruction, and flood risk in alpine valleys.
The community of Blatten, already evacuated, faced devastation after an estimated three million cubic meters of rock and ice crumbled from the Birch glacier, with scientists warning that similar glacier collapses and landslides may become more common as global warming continues. The health and wellness of the affected residents are now a concern, amid a growing lake upstream formed by the debris blocking the Lonza River, which poses a risk of catastrophic flooding for communities downstream, including Gampel and potentially the Rhone Valley. In addition, the environmental-science community emphasizes that climate change-fueled glacier loss and shrinkage, such as the recent losses in Swiss glaciers amounting to ten percent of their mass in just the years 2022 and 2023, pose interconnected risks to alpine communities and river systems. Furthermore, the science behind these events reveals that the rising temperatures and thawing permafrost make the entire slope more prone to collapse, underscoring the inevitable impact of climate change on the environment and the communities that inhabit it.
