Restricted accessOtherFirst published online 2011-3
Climate influence on rockfalls in high-Alpine steep rockwalls: The north side of the Aiguilles de Chamonix (Mont Blanc massif) since the end of the ‘Little Ice Age’
Rockfalls fundamentally affect the morphodynamics of high mountain rockwalls, and represent a great danger for both people and infrastructures, but still are poorly known. By comparing old, recent and new photographs, in addition to geomorphological field data, we propose an inventory of the rockfalls that occurred since the end of the ‘Little Ice Age’ on the north side of the Aiguilles de Chamonix (Mont Blanc massif), ranging in volume from 500 to 65 000 m 3. These 42 rockfalls occurred after 1947, of which > 70% during the last two decades, with a maximal frequency during the warm summers, especially in 2003. Average elevation of scars (3130 m a.s.l.) close to the lower modelled permafrost limit, and the topography (e.g. spurs) of the affected rock faces enhancing lateral heat fluxes, suggest that a climatically driven permafrost degradation has triggered many of the recent rockfalls in high-Alpine steep rockwalls.
Beniston M. ( 2003) Climatic change in mountain regions: A review of possible impacts. Climatic Change59: 5-31.
2.
Beniston M. ( 2004) The 2003 heat wave in Europe. A shape of things to come?Geophysical Research Letters31: 2022-2026.
3.
Beniston M. ( 2005) Mountain climates and climatic change: An overview of processes focusing on theEuropean Alps. Pure and Applied Geophysics162: 1587-1606.
4.
Beniston M., Diaz HF and Bradley RS ( 1997) Climatic change at high elevation sites: A review . Climatic Change36: 233-251.
5.
Böhlert R., Gruber S., Egli M., Maisch M., Brandová D., Ivy-Ochs S. et al. (2008) Comparison of exposure ages and spectral properties of rock surfaces in steep, high Alpine rock walls; a field study at Aiguille du Midi (France). In: Kane DL and Hinkel KM (eds) Proceedings of the 9th International Conference on Permafrost 2008. Institute of Northern Engineering - University of Alaska Fairbanks, 143-148.
6.
Casty C., Wanner H., Luterbacher J., Esper J. and Böhm R. ( 2005) Temperature and precipitation variability in the European Alps since 1500. International Journal of Climatology25: 1855-1880.
7.
Davies MCR, Hamza O. and Harris C. ( 2001) The effect of rise in mean annual temperature on the stability of rock slopes containing ice-filled discontinuities. Permafrost and Periglacial Processes12: 137-144.
8.
Deline P., Coviello V., Cremonese E., Gruber S., Krautblatter M., Jaillet S. et al. (2009) L’Aiguille du Midi (massif du Mont Blanc): Un site remarquable pour l’étude du permafrost des parois d’altitude . Collection EDYTEM8: 135-146.
9.
Evans SG and Gardner JS ( 1989) Risques de catastrophes naturelles dans la Cordillère canadienne. In: Fulton RJ (ed.) Le Quaternaire du Canada et du Groenland1: 756-767.
10.
Fischer L., Kääb A., Huggel C. and Noetzli J. ( 2006) Geology, glacier changes, permafrost and related slope instabilities in a high-mountain rock wall: Monte Rosa east face, Italian Alps. Natural Hazards and Earth System Sciences6: 761-772.
11.
Fish AM and Zaretsky YK ( 1997) Ice Strength as a Function of Hydrostatic Pressure and Temperature. Cold Region Research and Engineering Laboratory, Technical Report, 97-6.
12.
Gruber S. and Haeberli W. ( 2007) Permafrost in steep bedrock slopes and its temperature-related destabilization following climate change. Journal of Geophysical Research112: F02S18, doi:10.1029/2006JF000547.
13.
Gruber S., Hoelzle M. and Haeberli W. ( 2004a) Rock-wall temperatures in the Alps: Modelling their topographic distribution and regional differences. Permafrost and Periglacial Processes15: 299-307.
14.
Gruber S., Hoelzle M. and Haeberli W. ( 2004b) Permafrost thaw and destabilization of Alpine rock walls in the hot summer of 2003. Geophysical Research Letters31: L13504, doi:10.1029/ 2004GL020051.
15.
Haeberli W., Wegmann M. and Vonder Mühll D. ( 1997) Slope stability problems related to glacier shrinkage and permafrost degradation in the Alps. Eclogae Geologicae Helvetiae90: 407414.
16.
Harris C., Arenson LU, Christiansen HH, Etzelmüller B., Frauenfelder R., Gruber S. et al. (2009) Permafrost and climate in Europe: monitoring and modelling thermal, geomorphological and geotechnical responses. Earth Science Reviews92: 117-171.
17.
Intergovernmental panel on Climate Change ( 2007) Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge : Cambridge University Press.
18.
Noetzli J., Gruber S., Kohl T., Salzmann N. and Haeberli W. ( 2007) Three-dimensional distribution and evolution of permafrost temperatures in idealized high-mountain topography. Journal of Geophysical Research112: F02S13, doi:10.1029/2006JF000545.
19.
Ravanel L. and Deline P. ( 2008) La face ouest des Drus (massif du Mont Blanc): Évolution de l’instabilité d’une paroi rocheuse dans la haute montagne alpine depuis la fin du petit âge glaciaire. Géomorphologie4: 261-272.
20.
Ravanel L., Allignol F., Deline P., Gruber S. and Ravello M. ( 2010) Rockfalls in the Mont Blanc Massif in 2007 and 2008. Landslides DOI: 10.1007/s10346-010-0206-z.
21.
Schär C., Vidale PL, Luthi D., Frei C., Haberli C., Liniger MA et al. (2004) The role of increasing temperature variability in European summer heatwaves. Nature427: 332-336.
Vincent C. ( 2002) Influence of climate change over the 20th century on four French glacier mass balances. Journal of Geophysical Research107: 4375, DOI: 10.1029/2001JD000832.
