The detachment of a large part of the Birch glacier poured on the village downstream, already evacuated, a mountain of ice, rock and mud.
Wednesday 28 May around 3:30 pm A huge portion of the Birch glacierin southern Switzerland, collapsed downstream pouring millions of tons of rock, mud and ice on the underlying village of Blatten. The small center of the Canton Valava at 1,500 meters above sea level, where about 300 people resided, went 90% destroyed. Fortunately, the entire population had previously been evacuated for safety reasons, together with all the cattle. At the moment a village inhabitant is missing.
The mountain in crumbs. The impressive images of the collapse have gone around the web: the testimony of the state of precariousness in which the Alpine glaciers are poured, and of the natural disasters that all this can trigger.
The race towards the valley. For weeks the Swiss authorities had launched the alarm on the possibility of An imminent detachment of the glacierafter the appearance of crevasses in several points and the accumulation of rocky material estimated at 9 million tons on the mountain side. The weight of the debris had accelerated the movement downstream of the glacier Until the speed of 10 meters per day reach him in recent times. On May 19, the evacuation order had triggered after the alarm of the geologists of high instability.
The earthquake and the barred river. From the previous night, the collapse had been observed an increase in small detachments. On the afternoon of May 28, an imposing part of the glacier detached all at once, suddenly. The collapse caused a minor earthquake, with a magnitude 3.1 on the Richter scale (which measures the released energy), causing a shock wave and a perceptible movement of air and a brief interruption of current. The debris then have The course of the Lonza river is obstructedwhich crosses Blatten, arousing concerns about possible floods.
The paw of the climatic crisis. Global warming is making the glaciers, starting with the Alpine ones, more unstable. The Swiss ones have lost 10% of their overall volume only between 2022 and 2023
Frequency matter. However, it is difficult to understand if what happened in the village of Blatten would have happened anyway, without the influence of the climatic crisis. So Mylène Jacquemart, geographer of Hut Zurich, felt by New Scientist: «The changes induced by climate change in the high mountain regions (more melting water, less snowy coverage, higher temperatures, more rainfall that fall in the form of rain rather than snow) are not favorable for the stability of the rocks.
But would it have happened even without climate change? Probably yes. The fundamental question for risk management is If there is a substantial change as often certain events occur. An event that usually occurs every 10 years suddenly occurs every year? At this point, we still don’t see a clear quality leap for such imposing events ».
