The Swiss Glaciers 2005/06 and 2006/07

Abstract

During the 127th and 128th year under review by the Cryospheric Commission, Swiss glaciers continued to lose both length and mass. The dominant weather conditions of this measurement period and the effects of global warming left clear traces. In autumn 2006, a length variation was determined for 92 of the 98 glaciers observed, while one year later such a result was obtained for 91 of 95 glaciers. In the two observation periods, 2005/2006 and 2006/2007, Swiss glaciers experienced further losses in length. Most of the measurement values lie between 0 and -30 m in both of these periods. Detailed mass balance figures were obtained for the three glaciers Bas`odino, Gries and Silvretta, and point measurements were taken at several additional glaciers. The glaciers suffered significant mass losses in both periods. The two periods rank third and forth negative in the long-term statistics only exceeded by the two extreme periods 2002/03 and 1997/98. In contrast to the period 2002/03 with the hot summer the negative balances in the two reported periods are mainly due to reduced precipitation in winter. Flow measurements were taken at selected glaciers in the Mauvoisin and Mattmark regions. The trend continued toward diminishing velocities, a clear reflection of the reduction in ice thickness due to lasting negative mass balances of the glaciers. The awareness of the role of the glaciers as a component in the water cycle has grown in the general public in recent years. High melt rates in summer are observed with increasing concern. Large attention received the impacts of continuous glacier retreat, as of Unterer Grindelwaldgletscher where a large rock mass collapsed due to the no longer existing back pressure by the thinned glacier tongue.