Eiger Fall

Site of impending rock fall on the Eiger (at bottom centre of picture)
Originally from by Swiss TV SF 1.

Today's Guardian reports the imminent collapes of 2 million cubic metres of rock from the East face of the Eiger. A crack, was noticed a few weeks ago, it is 250 m long and is now opening at around 75 cm a day. The satellite image on Google Maps gives a decent idea of the location. The dark triangular shadow of the Eiger Nordwand is distinctive, just under the name Alpiglen. A long ridge, the Mitteligrat, leads East-North-East from the summit, finishing as the Hoernli above a narrow gorge which discharges meltwater from many glaciers (the Gletscherschlucht). The area of impending rock fall lies to the S of this ridge, above the tongue of the Lower Grindelwald Glacier. The location of the detaching rock nose is in the Schlosslouwina, a better (colour) map can be found at gis.swissinfo.org: search for Grindelwald.

According to the Neue Zurcher Zeitung, the probable cause of the crack is the retreat of the glacier, which has been losing about a metre's thickness each year for the past 20 years. In many alpine areas glaciers (and the associated permafrost) prop up rock faces. Once this support is lost, falls are likely.

Authorities are anticipating problems with dust from pulverised rock and the associated air pressure wave. Rock (or its powdered remnants) may also block the gorge, which will create a serious hazard from the impounded glacial meltwater. in 2003, bits dropping off the glacier created a 2 m high wave which travelled all the way down the valley to Interlaken.

Apparently, its become a tourist draw!

Although it is undoubtedly linked to glacial retreat, which in turn is being accelerated by global warming, one would think that it is an unusual event in the Alps. On the contrary, rock falls are happening all the time, although ones of this size are relatively rare: the Times says its the largest for 15 years. Once one looks at a Geology Map of the Alps its clear that large rock falls are a widespread phenomenon. Here's just a sampling:

Flimser Bergsturz/Alta Ruina

Rheinschlucht in Graubünden
Originally uploaded by rytc.

The largest known in the Alps occurred around 15,000 years ago, just as the valley glaciers retreated, in the Anterior Rhine valley. Some 15 cubic kilometres of rock collapsed (7,500 times the size of the Eiger rock), damming the river, which rapidly cut an impressive gorge (the Alta Ruina) through several hundred metres of crushed rock. Above the gorge the Rhine valley opens out into an area called the Foppa &en this flatter surface is the remnant of the lake bed.

Panorama Flimser Felssturz
Originally uploaded by falcion2000

This 'photo shows the village of Flims, which is built on debris from the landslide: the cliffs above are where the fracture took place. Flims is at 1100 m asl, the Rhine flows at around 600 m asl, and a couple of kilometres away, so its cutting through nearly 500 m of debris. The gorge, billed as "The Swiss Grand Canyon", is a good walk (about 20 km from Ilanz to Trin), or for the lazy, a great train ride. It also gives some good water for rafters and kayakers. Rhine cutting through debris from the Flims landslide


Goldauer Bergstürz

This massive rockfall happened in September 1806, when a thick slice of rock slid from the peak of the Rossberg, over 1,000 m above the village, killing 457 people.

Elmer Bergsturz

The landslide at Elm is a slightly different category: it was not just a force of nature which killed people – their own actions played a role. I first came across a description of this disaster in Frank Smyth's An Alpine Journey, where he remarks how frequent large landslides are in the Himalaya. To quote parts of his narrative:

"More than fifty years ago the inhabitants of Elm sub­sisted partly by pastoral pursuits and partly by slate quarrying. The richest bed of slate was one that dipped into a mountain known as the Plattenbergkopf. The quar­rying was carried out with an entire lack of circumspec­tion. A hole some 200 yards in width was driven into the mountain to a depth of 75 yards without any supports for the roof. The result was that the mountain presently ex­hibited visible signs of instability and 1,500 feet above the quarry a rift opened up in it that lengthened and widened steadily year by year. By 1881 there was little doubt that a large fall must occur."

That summer was wet (as in Goldau before), and on September 10th rocks were falling. Quarrying stopped, but there was no evacuation. As Smyth continues ..."there was no longer any doubt left in the minds of the peasants that a catastrophe must occur, but with all the obstinacy and lack of imagination of their kind they refused to evacuate their homes, and even ventured to an inn near the foot of the stricken hill to watch the falling rocks."

A schoolmaster recorded what befell the next day:

"At 5.15 p.m. the first of two preliminary falls occurred. ... The first engulfed a forest on the Platten­bergkopf, poured over the quarry and spread out fanwise on the level valley floor. The avalanche stopped only a few yards short of an inn near the foot of the mountain where sightseers had foolishly gathered to watch the rock falls.
No one was killed or injured but the avalanche alarmed the people in the upper village and, too late, they began to move sick and aged persons and evacuate their homes.

"Seventeen minutes later there came a second fall. This destroyed several houses, including the inn, together with such sightseers as had remained in it, and a number of houses, killing altogether some twenty persons. It left a gash in the Plattenbergkopf, which united with the gash left by the first fall to undermine the peak and rob it of all support. It was obvious now that the whole mountain must come down, and the terrified people who escaped the second fall started to run frantically up the slopes of the Düniberg opposite to the Plattenbergkopf. According to one of the survivors, Meinrad Rhyner :"

"" Some were for turning back to the valley to render help, but I called to them to fly. Heinrich Elmer was carrying boxes, and was only twenty paces behind me when he was killed. There were also an old man and woman, who were helping along their brother, eighty years old ; they might have been saved if they had left him. I ran by them, and urged them to hasten."

"Four minutes elapsed after the second fall. Then, with terrible suddenness the upper portion of the Plattenbergkopf collapsed. According to observers lower down the valley, the enormous mass of rock, estimated at over 10,000,000 cubic yards, weighing some 20,000,000 tons, slid down­wards with extraordinary velocity until the foot of it reached the quarry. Then the topmost portion pitched forward across the valley on to the Diiniberg up which people were toiling desperately in an attempt to evade destruction. So clearly defined was this forward pitching of the avalanche that distant observers could discern the people beneath it on the Düniberg running uphill for their lives. Next instant they had been crushed like insects beneath the millions of tons of rock. Six only escaped, and four of these were blown like leaves through the air by the wind of the falling masses, and by some miracle deposited unharmed high up the mountainside."

The landslide killed 114 people.