CREUX DE LA LE (VS)
Historical glacier forefield
Elevation: 2350-2600m - Massif: Alpes Vaudoises (Sanetsch) - Commune: Savièse (VS)
The proglacial margin of the Sanetschhorn glacier (today entirely covered by debris) situated on the northern side of the Sanetschhorn features morphologies caused by the glacier advance during the Little Ice Age. One can observe in particular a push moraine, i.e. a large mass of frozen sediments, which was pushed, dragged and deformed by the progression of the glacier. Electrical resistivity measurements, that were performed in 1998 and repeated in 2012 and 2017, confirm the presence of (degrading) permafrost in the proglacial margin. However, the sediment cover is mostly unfrozen. Further measurements have been carried out in the nearby talus slopes.
Measurements and observations
Thermal (ground surface temperature : GST)
Geophysics (electrical resistivity, refraction seismic)
Occurence/absence of permafrost (locally debris-covered glacier) based on electrical resistivity measurements (data: 1998).
Mean annual ground surface temperature. The orange curve represents the mean temperature of the n sensors installed on the site (grey curves). The orange dotted line is the mean temperature observed since the beginning of the measurements.
Contribution of the annual Ground Freezing (sum of all daily mean values < 0°C) and Ground Thawing (>0°C) Indexes to the mean annual ground surface temperature (MAGST) on a set of selected locations (n) on the site with indication of the respective trend since the beginning of the time series. Or : how cold was the winter and how warm was the summer at the surface of the ground ?
Mean annual dates of the start and end of the snowmelt period (zero curtain phase). Mean of n sensors localized on permafrost terrain.
Department of Geography, Ghent University (Belgium), H. Hendrickx
Delaloye, R. (2004). Contribution à l’étude du pergélisol de montagne en zone marginale. PhD thesis, Fac. Sciences, Univ. Fribourg, GeoFocus 10 (pdf)
Lambiel, C. & Delaloye, R. (2004). Contribution of real-time kinematic GPS in the study of creeping mountain permafrost: examples from the Western Swiss Alps. Perm. Perigl. Proc. Vol. 15/3, 229-241. DOI: 10.1002/ppp.496
Delaloye, R., Devaud, G. (2000). La distribution du pergélisol dans les marges proglaciaires des glaciers de Challand, d’Aget et du Sanetschhorn (Valais, Alpes suisses). HEGG, CH., VONDER MÜHLL, D. (Hrsg.) : Beiträge zur Geomorphologie. Proceedings der Fachtagung der Schweizerischen Geomorphologischen Gesellschaft vom 8.-10. Juli 1999 in Bramois (Kt. Wallis). Birmensdorf, Eidgenössischen Forschungsanstalt WSL, 89-96.