Cornice are formed by snow drift at plateau breaks, ridges or ridges directly on the leeward and mainly steeper side of a ridge. They have a sweeping overhang on the leeward side . When the wind direction changes, no cornices are formed on the flatter side, and with the same inclination on both sides of the ridge (isosceles triangle), no cornices are usually formed either. The cornice wedge arises under the cornice - an unstable snow deposit, often the cause of avalanches.
Cornice are extremely treacherous for mountaineers, touring and extreme skiers. If you enter the flatter apex of the cornices, which appears more favorable, above the corneal gap, the cornices can break off. The cornice gap - a kind of predetermined breaking point of a cornice - is a gap usually covered by snow between the snow cover on the windward side and the overhanging cornices on the leeward side. It is caused by settlement processes and creeping movements of the cornices and runs on the windward side a little below the ridge edge given in the rock. The corneal cleft is often impossible or difficult to see, which makes it difficult to lay a safe trail. Since the cornice gap does not run vertically over the edge of the ridge and the track has to be kept at a sufficient safety distance in the flank, the distance to the edge of the cornices increases. As a result, the usual strategy in a rope team - walking on the shortened rope and jumping to the opposite side if a partner falls - can no longer be used and securing the rope team becomes problematic. In such a case, it can be cheaper to go from the shortened rope to the full rope length. In the period from February 2 to April 18, 2013, the Austrian Mountain Rescue Service reported nine fractures with five dead and five injured.
In addition to mountain climbers, the weight load from fresh snow or the destabilization of the snow structure when the temperature rises can cause the cornices to break off. Broken cornices can also trigger avalanches .
The well-known Austrian mountaineer Hermann Buhl , the first to climb Nanga Parbat , died in a broken cornice in the Karakoram on the Chogolisa (he is believed to be lost). Likewise, Fritz Kasparek , who was one of the first to climb the north face of the Eiger , had a fatal accident on the summit ridge of the Salcantay in Peru. The French extreme mountaineer Patrick Berhault also died from broken fractures on the Täschhorn (Wallis). Alfred Pallavicini , namesake of the Pallavicini Gully , died on June 26th, 1886 while first climbing the Glocknerwand after a broken cornice just below the summit. Stéphane Brosse died on June 17, 2012 of a broken cornea on the Aiguille d'Argentière . On April 16, 2019, David Lama , Hansjörg Auer and Jess Roskelley were hit by a broken cornea on Howse Peak and torn 800 meters into the depth.
Alternating cornices on the Rochefort ridge in the Mont-Blanc area
Wechte at the front end
Wechtenbruch on the Wildspitze caused by a mountaineer in April 1997 without consequences. On April 4, 2009, a mountaineer fatally fell from a fracture at the same point.
Schneewechte on the Simplon Pass
- Cornices. At: gudelius.de.
- Wilhelm Welzenbach : Investigations on the stratigraphy of the snow deposition and the mechanics of the snow movement together with the conclusion on the methods of the construction. Karlsruhe 1930, Wissenschaftl. Publications d. D. u. Ö. Alpine Club. No. 9.
- Pepi Stückl, Georg Sojer: Mountaineering: Textbook for all types of mountaineering. Bruckmann, Munich 1996, ISBN 3-7654-2859-0 , p. 132.
- Paul Mair: On the safe side. (PDF; 1.1 MB) bergundstieg.de, August 4, 2009, pp. 60–62 , accessed on June 19, 2012 (interview and pictures of the accident).