Eiger face falls....

[Dr Mordrid]

http://www.nature.com/news/2006/060717/full/060717-3.html

The Eiger, Switzerland's most infamous mountain, is traditionally best known for the challenge of ascending its north face. But it gained fame in another way last week when a huge chunk fell from its eastern flank, triggering claims that climate change has been implicated in yet another high-profile natural event.

Geologists predicted the rockfall last month, after noting that large cracks were working their way into the mountain's side. The crash finally came on 13 July: Swiss rescue services estimate that some 700,000 cubic metres of rock — the size of a large skyscraper— have tumbled into the valley below.

[Brian Ellis]

And this is just a small part of the loose rock.

What worries me much more is if something similar happens in China above the Three Gorges Dam lake after it has been filled. The rock faces there are notoriously unstable. If the resultant wave overflowed the dam, it could be a major catastrophe: there is a 2 million inhabitants city just 20 km downstream. When I visited the site, I actually witnessed a small landslide into the Yangtze but, in places, the mountain sides actually overhang the river. Nobody has a clue what the effect of damming up nearly 100 billion tonnes of water in a seismic valley will be. The ayesayers say no effect; the naysayers that it will be sure catastrophe that could kill many millions. Take your pick.