Last night a fatal rockfall occurred at Stein an der Traun in Southern Bavaria. According to this report, which is also the source of the remarkable image above, the block was the "size of a house" (probably something of an over-estimate), falling from the 15 m slope behind the building. There were four people in the house at the time, of which two were killed and two were injured. There is no obvious trigger for the failure.
It is of course too early to speculate about the causes of this sad accident, but in my experience the combination of an unfortunately-orientated discontinuity in the rock (often a joint) and cutting of the toe of the slope to create space for the building are often to blame. It will be interesting to find out what caused this accident.
The bavarian geologist Andreas von Poschinger estimates a total mass of 250 tons. The rock is a quite young (200ka) conglomerate and called "Nagelfluh" in German. The rockfall might have been caused by frost-wedging.
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