The sliding of the upper part of the scree above Brienz in Graubünden has accelerated significantly. Up to 1.2 million m3 of rocks could move towards the village, announced the municipality of Albula. The municipal staff is preparing a preventive evacuation. If the moving rock mass reaches a high speed, it could slide past the existing alluvial fan and reach the entire village. For security reasons, the general staff therefore decided to move to the “yellow phase”. However, the time for the evacuation has not yet been set, it was clarified on Saturday.
Measurements from the early warning service showed that the upper part of the scree had been moving at a rate sometimes exceeding 30 centimeters per day since the second half of September. A lull in the situation is expected, but a collapse cannot be ruled out, according to the municipal staff. It could be triggered by new precipitation, by a slide of rocks from the top of the scree or by the speed of the slide. The municipal management staff intends to inform the population of the current situation and the measures planned for Saturday evening in Tiefencastel. Experts in geology and natural hazards as well as officials from the canton of Graubünden will be present.
Huge debris flow in 2023
The last evacuation of Brienz dates back to May 12, 2023: up to two million cubic meters of rock threatened to collapse from the mountain slope above the village, the equivalent of 2,000 individual houses. On the night of June 16, 2023, 1.2 million cubic meters of rock broke away in the form of a huge flow, which stopped just before the village. At the beginning of July 2023, the residents of Brienz were able to return to their homes.
In mid-March 2024, a few thousand cubic meters of rock broke away again above the town, without affecting the village. The plateau, a stratum of land of 5 million m3 overlooking the village, sliding towards the valley at a rate of 4.3 meters per year, new cracks have formed. Parts of the wall came off. In May this year, heavy rainfall caused an increase in rockfall from this slide. But the village was spared.
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