Permafrost distribution in talus slopes located within the alpine periglacial belt, Swiss Alps

The extent of permafrost in nine talus slopes located within the alpine periglacial belt in the western Swiss Alps was investigated using ground surface temperature measurements and one‐ dimensional geoelectrical profiles. Based on the thermal data, permafrost appears likely in the lower parts of the slopes. At the same locations, an electrically resistive layer, interpreted as frozen sediments, was identified beneath 3–5 m of surface materials. Further upslope, resistivities were lower and ground surface temperatures were warmer, suggesting that permafrost was absent. The cooling of the ground in the lower parts of some of the talus slopes investigated was apparently due to the chimney effect. It is inferred that this mechanism plays an important role in permafrost development in the lower half of talus slopes located within the discontinuous mountain permafrost belt. Copyright © 2008 John Wiley & Sons, Ltd.