Swiss tourists flock to watch Eiger mountain crumble into valley

Thousands of Swiss are flocking to one of the country's most famous mountains to catch a last glimpse of its dramatic outline, before a slab of rock weighing millions of tons breaks off from its eastern face and falls into the valleys below.

The Eiger, one of Europe's most treacherous peaks, has been crumbling at an almost visible rate for the past month and experts believe it is only a matter of days before five million tons of rock come crashing down.

The slab, equivalent in volume to two Empire State buildings, is moving away from the rockface at a rate of 35 inches a day. A fissure between the two surfaces first spotted at the beginning of June has grown from eight inches to more than 16ft.

It is thought that climate change is behind the Eiger's dramatic change. The Grindelwald glacier, which used to support the rockface, is melting due to higher temperatures and water in the fissure is building up pressure.

The demise of one of their much-loved national treasures is not something the Swiss are willing to miss. Crowds of sightseers have arrived in the past few weeks to watch it crumbling. Anita Bauer, from Austria, travelled to the Bernese Oberland with her husband and two children especially to see this "once in a lifetime event". Like many others, she decided to stay in the Berghaus Bäregg, a mountain restaurant which provides a bird's eye view of the frequent secondary rock fall heralding the main event. The biggest so far involved about 1,000 cubic metres of rock and created a huge cloud of dust in the vicinity.

When it occurs, the rock fall will be the largest Europe has seen for 15 years. Although part of the Grindelwald Glacier has been closed off, neither the restaurant nor the resort of Grindelwald, which nestles beneath the north face of the Eiger, is considered to be at risk.

Warning signs have been posted on hiking routes around the site, advising tourists that when the outcrop finally tumbles it will feel like an earthquake. They can expect to be deafened by the crash and blinded by clouds of debris, experts say, but this is not a reason to panic. Mountain rescue teams have been put on special alert.

The crumbling Eiger is a particularly prominent example of the instability recently evident throughout the Alps. At the end of May, a spectacular rock fall on one of Europe's primary trans-alpine road routes, the Gotthard, killed two German motorists. The Gotthard road, Switzerland's main north-south route, was closed for a month, causing traffic chaos between Germany and Italy. And on Monday this week, a 70-year-old German hiker was killed by a huge mudslide which descended from a glacier in the Grisons region of Switzerland.